CVE-2026-44740 — v5
MEDIUMCVE-2026-44740 is a medium-severity (CVSS 6.5) CWE-674 vulnerability in github.com/go-git/go-billy/v5. A fix is available for github.com/go-git/go-billy/v5 — see the affected versions and patch details below.
go-billy: Lack of depth and cycle detection in symlink resolution may lead to infinite loops and resource exhaustion
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-2026-44740.
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-2026-44740 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 378,567 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-billy/v5🐹github.com/go-git/go-billy/v6Real-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
Multiple components may improperly handle crafted or malformed input, resulting in panics, infinite loops, uncontrolled recursion, or excessive resource consumption.
These issues arise from insufficient validation and missing safety mechanisms such as cycle detection, recursion limits, or defensive handling of unexpected states when processing untrusted repository data and filesystem structures.
Patches
Users should upgrade to a patched version in order to mitigate this vulnerability. Versions prior to v5 are likely to be affected, users are recommended to upgrade to a supported go-billy version.
Credits
Thanks to @faran66 for finding and reporting this issue privately to the go-git project. 🙇
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/go-git/go-billy/v5 | all versions | 5.9.0go get github.com/go-git/go-billy/v5@v5.9.0 |
| 🐹Go | github.com/go-git/go-billy/v6 | all versions | 6.0.0-alpha.1go get github.com/go-git/go-billy/v6@v6.0.0-alpha.1 |
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-billy/v5, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/go-git/go-billy/v5 to 5.9.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-44740 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-2026-44740 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-44740. 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.
This is rated as an Important severity issue. The `go-billy` library, a Go filesystem abstraction, is vulnerable to a denial of service when processing crafted or malformed input, such as untrusted repository data or filesystem structures. Insufficient validation and missing safety mechanisms can lead to panics,…
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Enterprise Linux 8 | grafana-0:9.2.10-32.el8_10 | RHSA-2026:46391 |
| RHEM 1.1 for RHEL 10 | flightctl-0:1.1.4-1.el10em | RHSA-2026:68334 |
| RHEM 1.2 for RHEL 10 | flightctl-0:1.2.1-1.el10 | RHSA-2026:68335 |
| Cluster Observability Operator 1.5.0 | cluster-observability-operator/perses-rhel9:1787593946 | RHSA-2026:61314 |
| external secrets operator for Red Hat OpenShift 1.1 | external-secrets-operator/external-secrets-rhel9:1786614676 | RHSA-2026:54525 |
| multicluster engine for Kubernetes 2.1 | multicluster-engine/cluster-image-set-controller-rhel9:1784646026 | RHSA-2026:46885 |
| multicluster engine for Kubernetes 2.1 | multicluster-engine/cluster-image-set-controller-rhel9:1784646026 | RHSA-2026:47388 |
| multicluster engine for Kubernetes 2.11 | multicluster-engine/cluster-image-set-controller-rhel9:1786911957 | RHSA-2026:57194 |
Frequently Asked Questions
Is CVE-2026-44740 in your dependencies?
O3 Security finds CVE-2026-44740 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.