GitPython: Unguarded git read-tree option forwarding in IndexFile.from_tree/reset/merge_tree enables arbitrary file overwrite

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

8.1 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H

EPSS

• CVE-2026-76219: 0.54% estimated exploitation activity in the next 30 days; percentile 45.67 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary IndexFile.fromtree, IndexFile.reset (→ fromtree) and IndexFile.mergetree append caller-influenced treeish strings positionally to git read-tree with no unsafe-option guard, no allowunsafeoptions 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 checkoutindex and tag; readtree was left unprotected (it is among the acknowledged unguarded call sites in that advisory's sweep but was never reported or fixed). Root Cause fromtree (index/base.py:388), reset (delegates to fromtree), and mergetree (index/base.py:291) call repo.git.readtree(arglist) with no checkunsafeoptions and no --. The treeish is caller-influenced and positional. Impact Arbitrary file overwrite /…

Published by the source

7 Aug 2026, 15:33 UTC

Last modified by the source

8 Sep 2026, 20:54 UTC

Source last checked

26 Oct 2026, 13:51 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-4gmw-gg2m-w46p

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# Patch Next advisory brief: CVE-2026-76219

Advisory: GitPython: Unguarded git read-tree option forwarding in IndexFile.from_tree/reset/merge_tree enables arbitrary file overwrite
IDs: CVE-2026-76219, GHSA-4gmw-gg2m-w46p
Record: https://patchnext.com/advisories/cve-2026-76219 (revision 1, source checked 26 Oct 2026, 13:51 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: gitpython 3.1.58. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI gitpython: affected <= 3.1.57; fixed in 3.1.58

## Suggested inspection (read-only)
- `python -m pip show gitpython`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on gitpython.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-4gmw-gg2m-w46p (GitHub-reviewed advisory GHSA-4gmw-gg2m-w46p lists affected ranges: PyPI gitpython >=0 <=3.1.57)

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