CVE-2026-25934 — v5
MEDIUMCVE-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
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
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2026-25934 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,333 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
github.com/go-git/go-git/v5Real-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
go-git is a highly extensible git implementation library written in pure Go. Prior to 5.16.5, 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. This vulnerability is fixed in 5.16.5.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/go-git/go-git/v5 | all versions | 5.16.5go get github.com/go-git/go-git/v5@v5.16.5 |
Detection & mitigation playbook
Open-source dependencyDetect
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.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-25934 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-25934. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
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.
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Openshift Data Foundation 4.22 | odf4/cephcsi-rhel9:1782932114 | RHSA-2026:37387 |
Frequently Asked Questions
Is CVE-2026-25934 in your dependencies?
O3 Security finds CVE-2026-25934 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.