CVE-2026-44973

Credits

Thanks to @faran66 and @vnykmshr for finding and separately reporting this issue privately to the go-git project. 🙇

Multiple path traversal issues exist across different components of go-billy. Insufficient path sanitization and boundary enforcement may allow crafted paths (e.g., using ..) to escape intended base directories.

While go-billy was not originally designed to provide a strong security boundary, some of these issues were inconsistent across some of the built-in implementations. This results in scenarios where applications relying on go-billy for some level of isolation may inadvertently expose access to unintended filesystem locations.

The osfs.ChrootOS implementation is notably affected by this vulnerability and is now deprecated in v5, removed at v6. Users are recommended to move on to osfs.BoundOS instead: osfs.New(path, WithBoundOS()).

Users requiring stronger security boundary enforcement are recommended to upgrade to v6, where the osfs implementation are backed by the traversal-resistant primitive os.Root.

Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files. Typical impact: unauthorized file read or write outside the intended directory.

CVE-2026-44973 has a CVSS score of 8.1 (High). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (5.9.0, 6.0.0-alpha.1); upgrading removes the vulnerable code path.

Kodem intelligence

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.

1. What is CVE-2026-44973? CVE-2026-44973 is a high-severity path traversal vulnerability in github.com/go-git/go-billy/v5 (go), affecting versions < 5.9.0. It is fixed in 5.9.0, 6.0.0-alpha.1. Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files.
2. How severe is CVE-2026-44973? CVE-2026-44973 has a CVSS score of 8.1 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which packages are affected by CVE-2026-44973?
   • github.com/go-git/go-billy/v5 (go) (versions < 5.9.0)
   • github.com/go-git/go-billy/v6 (go) (versions < 6.0.0-alpha.1)
4. Is there a fix for CVE-2026-44973? Yes. CVE-2026-44973 is fixed in 5.9.0, 6.0.0-alpha.1. Upgrade to this version or later.
5. Is CVE-2026-44973 exploitable, and should I be worried? Whether CVE-2026-44973 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-44973 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-44973?
   • Upgrade github.com/go-git/go-billy/v5 to 5.9.0 or later
   • Upgrade github.com/go-git/go-billy/v6 to 6.0.0-alpha.1 or later