What is CVE-2026-76219?

## Summary `IndexFile.from_tree`, `IndexFile.reset` (→ from_tree) and `IndexFile.merge_tree` append caller-influenced treeish strings positionally to `git read-tree` with no unsafe-option guard, no `allow_unsafe_options` parameter, and no `--` separator. `git read-tree --index-output= ` writes the resulting index to an arbitrary path, and last-occurrence-wins lets an injected `--index-output` override the method's internal temp path — clobbering an arbitrary file with a valid git-index blob. This is a distinct, never-guarded sink: commit `3af0c251` (GHSA-3f7w-8rr8-f37f) guarded only `chec

How severe is CVE-2026-76219?

No CVSS score has been assigned to CVE-2026-76219 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-76219?

CVE-2026-76219 affects the following packages: gitpython (PyPI). Ecosystems affected: PyPI.

How do I fix CVE-2026-76219?

Update gitpython to 3.1.58 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-76219 is resolved across your whole dependency graph.

How do I detect CVE-2026-76219 in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for gitpython, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-76219 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2026-76219 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-76219 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-76219?

CVE-2026-76219 has an EPSS (Exploit Prediction Scoring System) score of 0.5%, placing it in the 44th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-76219?

CVE-2026-76219 is classified as CWE-88 (CWE-88). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-76219 published, and has it been updated?

CVE-2026-76219 was published on August 19, 2026 and was last updated on September 25, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍 PyPI

Not in CISA KEV

CVE-2026-76219 — gitpython

Fix: gitpython-developers/GitPython#2204

CVE-2026-76219 is a CWE-88 vulnerability in gitpython. A fix is available for gitpython — see the affected versions and patch details below.

GitPython before 3.1.58 Arbitrary File Overwrite via read-tree

Also known asGHSA-4gmw-gg2m-w46pPYSEC-2026-3838

Published

Aug 19, 2026

Updated

Sep 25, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 2, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

0.5%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs44th percentile — riskier than 44% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

🐍gitpython

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

Summary

IndexFile.from_tree, IndexFile.reset (→ from_tree) and IndexFile.merge_tree append caller-influenced treeish strings positionally to git read-tree with no unsafe-option guard, no allow_unsafe_options parameter, and no -- separator. git read-tree --index-output=<file> writes the resulting index to an arbitrary path, and last-occurrence-wins lets an injected --index-output override the method's internal temp path — clobbering an arbitrary file with a valid git-index blob. This is a distinct, never-guarded sink: commit 3af0c251 (GHSA-3f7w-8rr8-f37f) guarded only checkout_index and tag; read_tree was left unprotected (it is among the acknowledged unguarded call sites in that advisory's sweep but was never reported or fixed).

Root Cause

from_tree (index/base.py:388), reset (delegates to from_tree), and merge_tree (index/base.py:291) call repo.git.read_tree(*arg_list) with no check_unsafe_options and no --. The treeish is caller-influenced and positional.

Impact

Arbitrary file overwrite / destruction at the privileges of the host process. Content is constrained to a git-index blob (not attacker-chosen, so not RCE), but the target path is fully attacker-controlled — corrupting/truncating configs or destroying files at attacker-chosen writable locations = I:H + A:H (per the skill's "overwrite-any-path = I:H" rule). Pure VALUE control (positional treeish). Default configuration.

Proof of Concept

IndexFile.from_tree(repo, "--index-output=/home/victim/.bashrc")
# target overwritten with a valid git-index blob (DIRC...)

Attack Chain

Entry: app calls IndexFile.from_tree(repo, treeish) / reset(commit=…) / merge_tree(base=…, rhs=…) with attacker treeish="--index-output=/home/victim/.bashrc".
Check: NONE — the methods have no allow_unsafe_options and never call check_unsafe_options.
Sink: repo.git.read_tree(*arg_list) — no --. argv (from_tree, observed): ['git','read-tree','--index-output=<tmp>','--index-output=/…/victim'] (last-wins).
Impact: target path created/overwritten with a valid git-index blob; existing content destroyed.

Bypass Evidence

Independently reproduced (gate harness): IndexFile.from_tree(repo,'--index-output=<victim>') → victim overwritten; before=IMPORTANT ORIGINAL CONTENT, after starts DIRC\x00\x00\x00\x02… (destructive clobber, valid index blob). reset(commit=…) and both merge_tree positionals verified. Fix-commit read: 3af0c251 touched only checkout_index+tag; read_tree untouched on HEAD.

Affected Versions

GitPython <= 3.1.57 (sinks present verbatim on the latest release tag).

Suggested Fix

Add a check_unsafe_options guard (with an allow_unsafe_options parameter) to from_tree/reset/merge_tree, and/or place a -- separator before the positional treeish arguments; block --index-output (a path-taking option) on this sink.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`gitpython`	all versions	3.1.58`pip install --upgrade 'gitpython==3.1.58'`

Affected Products

1 product · 1 configurations

Application

gitpythongitpython_project

< 3.1.58

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for gitpython, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update gitpython to 3.1.58 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-76219 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatImportant

GitPython's IndexFile.from_tree, IndexFile.reset, and IndexFile.merge_tree append caller-influenced treeish strings to `git read-tree` without option validation or argument separation, letting an attacker who controls those arguments inject the `--index-output` option to overwrite arbitrary files at…

Workaround published by Red Hat

Do not pass untrusted or attacker-influenced treeish arguments to GitPython's IndexFile.from_tree, IndexFile.reset, or IndexFile.merge_tree. Upgrade to GitPython 3.1.58 or later, where option injection into `git read-tree` is fixed.

Source: Red Hat security advisory for CVE-2026-76219 (CC BY 4.0)

Product	Fixed in	Advisory
Red Hat Satellite 6.19 for RHEL 9	`python3.12-gitpython-0:3.1.59-1.el9pc`	RHSA-2026:63385
Red Hat Ansible Automation Platform 2.5	`ansible-automation-platform-25/controller-rhel8:1789607021`	RHSA-2026:71210
Red Hat Ansible Automation Platform 2.6	`ansible-automation-platform-26/controller-rhel9:1789673739`	RHSA-2026:71179
Red Hat Ansible Automation Platform 2.7	`ansible-automation-platform-27/controller-rhel9:1789580684`	RHSA-2026:71177
Red Hat Satellite 6.18	`satellite/iop-vmaas-rhel9:1789611858`	RHSA-2026:68764
Red Hat Satellite 6.18	`satellite/iop-vulnerability-engine-rhel9:1789637082`	RHSA-2026:68771
Red Hat Satellite 6.19	`satellite/iop-vulnerability-engine-rhel9:1789607605`	RHSA-2026:68776
Red Hat Satellite 6.19	`satellite/iop-vmaas-rhel9:1789611998`	RHSA-2026:68780

Frequently Asked Questions

## Summary `IndexFile.from_tree`, `IndexFile.reset` (→ from_tree) and `IndexFile.merge_tree` append caller-influenced treeish strings positionally to `git read-tree` with no unsafe-option guard, no `allow_unsafe_options` parameter, and no `--` separator. `git read-tree --index-output=<file>` writes the resulting index to an arbitrary path, and last-occurrence-wins lets an injected `--index-output` override the method's internal temp path — clobbering an arbitrary file with a valid git-index blob. This is a distinct, never-guarded sink: commit `3af0c251` (GHSA-3f7w-8rr8-f37f) guarded only `chec

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