go-git missing validation decoding Index v4 files leads to panic

Exploitation

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

CVSS

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

EPSS

• CVE-2026-33762: 0.18% estimated exploitation activity in the next 30 days; percentile 7.34 (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.

Impact `go-git`’s index decoder for format version 4 fails to validate the path name prefix length before applying it to the previously decoded path name. A maliciously crafted index file can trigger an out-of-bounds slice operation, resulting in a runtime panic during normal index parsing. This issue only affects Git index format version 4. Earlier formats (`go-git` supports only `v2` and `v3`) are not vulnerable to this issue. An attacker able to supply a crafted `.git/index` file can cause applications using go-git to panic while reading the index. If the application does not recover from panics, this results in process termination, leading to a denial-of-service (DoS) condition. Exploitation requires the ability to modify or inject a Git index file within the local repository in disk. This typically implies write access to the `.git` directory.

Patches Users should upgrade to `v5.17.1`, or the latest `v6` pseudo-version, in order…

Published by the source

30 Mar 2026, 17:05 UTC

Last modified by the source

2 Nov 2026, 23:15 UTC

Source last checked

3 Nov 2026, 06:10 UTC

1. Revision 3 · amended · 3 Nov 2026

   Amended from osv record GHSA-gm2x-2g9h-ccm8

2. Revision 2 · amended · 2 Nov 2026

   Amended from ghsa record GHSA-gm2x-2g9h-ccm8

3. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-gm2x-2g9h-ccm8

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# Patch Next advisory brief: CVE-2026-33762

Advisory: go-git missing validation decoding Index v4 files leads to panic
IDs: CVE-2026-33762, GHSA-gm2x-2g9h-ccm8
Record: https://patchnext.com/advisories/cve-2026-33762 (revision 3, source checked 3 Nov 2026, 06:10 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Low (CVSS 2.8)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/go-git/go-git/v5 5.17.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/go-git/go-git/v5: affected < 5.17.1; fixed in 5.17.1

## Suggested inspection (read-only)
- Go github.com/go-git/go-git/v5: check the installed version with your package manager.

## 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 github.com/go-git/go-git/v5.
- 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-gm2x-2g9h-ccm8 (GitHub-reviewed advisory GHSA-gm2x-2g9h-ccm8 lists affected ranges: Go github.com/go-git/go-git/v5 >=0 <=5.17.0)
- Verified: https://osv.dev/vulnerability/GHSA-gm2x-2g9h-ccm8 (OSV record GHSA-gm2x-2g9h-ccm8 lists affected ranges: Go github.com/go-git/go-git/v5 >=0 <5.17.1 (fixed))

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