How severe is CVE-2026-25934?

CVE-2026-25934 has a CVSS score of 4.3/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2026-25934?

CVE-2026-25934 affects the following packages: github.com/go-git/go-git/v5 (Go). Ecosystems affected: Go.

How do I fix CVE-2026-25934?

Update github.com/go-git/go-git/v5 to 5.16.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-25934 is resolved across your whole dependency graph.

How do I detect CVE-2026-25934 in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/go-git/go-git/v5, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-25934 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-2026-25934 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-25934 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-2026-25934?

CVE-2026-25934 has an EPSS (Exploit Prediction Scoring System) score of 0.2%, placing it in the 5th 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-2026-25934?

CVE-2026-25934 is classified as CWE-354 (CWE-354). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-25934 published, and has it been updated?

CVE-2026-25934 was published on February 9, 2026 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹

🐹 Go

Not in CISA KEV

MEDIUM severity

CVE-2026-25934 — go-git

MEDIUM

CVE-2026-25934 is a medium-severity (CVSS 4.3) CWE-354 vulnerability in github.com/go-git/go-git/v5. A fix is available for github.com/go-git/go-git/v5 — see the affected versions and patch details below.

go-git improperly verifies data integrity values for .idx and .pack files

Also known asGHSA-37cx-329c-33x3GO-2026-4473

Published

Feb 9, 2026

Updated

Oct 28, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 3, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-25934.

EPSS Exploitation Probability

via FIRST.org ↗

0.2%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs5th percentile — riskier than 5% of all scored CVEsHighest risk

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

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected

🐹github.com/go-git/go-git/v5

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

Description

Impact

A vulnerability was discovered in go-git whereby data integrity values for .pack and .idx files were not properly verified. This resulted in go-git potentially consuming corrupted files, which would likely result in unexpected errors such as object not found.

For context, clients fetch packfiles from upstream Git servers. Those files contain a checksum of their contents, so that clients can perform integrity checks before consuming it. The pack indexes (.idx) are generated locally by go-git, or the git cli, when new .pack files are received and processed. The integrity checks for both files were not being verified correctly.

Note that the lack of verification of the packfile checksum has no impact on the trust relationship between the client and server, which is enforced based on the protocol being used (e.g. TLS in the case of https:// or known hosts for ssh://). In other words, the packfile checksum verification does not provide any security benefits when connecting to a malicious or compromised Git server.

Patches

Users should upgrade to v5.16.5, or the latest v6 pseudo-version, in order to mitigate this vulnerability.

Workarounds

In case updating to a fixed version of go-git is not possible, users can run git fsck from the git cli to check for data corruption on a given repository.

Credit

Thanks @N0zoM1z0 for finding and reporting this issue privately to the go-git project.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/go-git/go-git/v5`	all versions	5.16.5`go get github.com/go-git/go-git/v5@v5.16.5`

Affected Products

1 product · 1 configurations

Application

go-gitgo-git_project

< 5.16.5

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/go-git/go-git/v5, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/go-git/go-git/v5 to 5.16.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-25934 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 HatModerate

Product	Fixed in	Advisory
Red Hat Openshift Data Foundation 4.22	`odf4/cephcsi-rhel9:1782932114`	RHSA-2026:37387

Frequently Asked Questions

### Impact A vulnerability was discovered in `go-git` whereby data integrity values for `.pack` and `.idx` files were not properly verified. This resulted in `go-git` potentially consuming corrupted files, which would likely result in unexpected errors such as `object not found`. For context, clients fetch [`packfiles`](https://git-scm.com/docs/pack-protocol#_packfile_data) from upstream Git servers. Those files contain a checksum of their contents, so that clients can perform integrity checks before consuming it. The pack indexes (`.idx`) are [generated](https://git-scm.com/docs/pack-forma