# CVE-2026-33762: go-git: Missing validation decoding Index v4 files leads to panic

Status: published. Published: 2026-03-31. Updated: 2026-11-02.

go-git is an extensible git implementation library written in pure Go. Prior to version 5.17.1, 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. This issue has been patched in version 5.17.1.

## Remediation

- fix: github.com/go-git/go-git/v5 (Go): OSV reports a fixed version 5.17.1. Check the advisory for supported release branches. (source: OSV GHSA-gm2x-2g9h-ccm8) — https://github.com/advisories/GHSA-gm2x-2g9h-ccm8

## Affected products and versions

- go-git / go-git: < 5.17.1 (affected). Source: CNA: GitHub_M
-  / github.com/go-git/go-git/v5 (github.com/go-git/go-git/v5): ≥ 0; < 5.17.1 (affected, semver); OSV events: introduced 0; fixed 5.17.1. Source: OSV GHSA-gm2x-2g9h-ccm8

## NVD configuration conditions

Affected CPE matches depend on the following AND/OR and negation conditions:

```json
[
  {
    "negate": false,
    "nodes": [
      {
        "cpeMatch": [
          {
            "criteria": "cpe:2.3:a:go-git_project:go-git:*:*:*:*:*:go:*:*",
            "versionEndExcluding": "5.17.1",
            "vulnerable": true
          }
        ],
        "negate": false,
        "operator": "OR"
      }
    ],
    "operator": "OR"
  }
]
```

## Severity and prioritization

- CVSS 3.1: 2.8 (low); CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:L; source: CNA: GitHub_M

- CVSS 3.1: 2.8 (low); CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:L; source: NVD: security-advisories@github.com

- CISA KEV: No listing in collected sources

- EPSS: 0.16% as of 2026-11-02; percentile 5.03%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-129

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/go-git/go-git/security/advisories/GHSA-gm2x-2g9h-ccm8 (CNA: GitHub_M; x_refsource_CONFIRM)

- https://github.com/go-git/go-git/commit/e9b65df44cb97faeba148b47523a362beaecddf9 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/go-git/go-git/releases/tag/v5.17.1 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/go-git/go-git/commit/e9b65df44cb97faeba148b47523a362beaecddf9 (security-advisories@github.com)

- https://github.com/go-git/go-git/releases/tag/v5.17.1 (security-advisories@github.com; Product, Release Notes)

- https://github.com/go-git/go-git/security/advisories/GHSA-gm2x-2g9h-ccm8 (security-advisories@github.com; Vendor Advisory)

- https://github.com/advisories/GHSA-gm2x-2g9h-ccm8 (OSV / GitHub Security Advisories; advisory)

- https://osv.dev/vulnerability/GHSA-gm2x-2g9h-ccm8 (OSV / GitHub Security Advisories; osv)

## Provenance

- CNA: GitHub_M: https://www.cve.org/CVERecord?id=CVE-2026-33762; retrieved 2026-11-02; source updated 2026-11-02

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-33762; retrieved 2026-11-03; source updated 2026-11-02

- OSV / GitHub Security Advisories: https://osv.dev/vulnerability/GHSA-gm2x-2g9h-ccm8; retrieved 2026-11-02; source updated 2026-09-10

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-33762; retrieved 2026-11-02; source updated Not reported

Revision: b95d471601940aa38d3f7276abc0417e972729de6c61a74c4677e7b70fb74457

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