GitPython CVE-2026-78679

The application must invoke GitPython's TagReference.create() method and allow attacker-controlled input to reach the positional reference parameter without prior sanitization. The CVSS 4.0 PR:L metric confirms that some level of authenticated or low-privilege access is required - unauthenticated exploitation is not supported by the available data. Exploitation is further limited to files readable by the OS account under which the application process runs, meaning a least-privilege deployment materially reduces the blast radius. There is no requirement for a non-default configuration of GitPython itself: the unsafe guard is a built-in mechanism, but the bypass occurs via positional argument passing regardless of how the guard is configured. Applications that never expose tag-creation functionality to user-controlled input are not exploitable.

The CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N) indicates network-reachable exploitation at low complexity requiring only low-privilege access, with high confidentiality impact confined to the vulnerable system. There is no integrity or availability impact, and no subsequent-system impact indicated. In practice, exploitability depends heavily on whether user-controlled input can reach the reference parameter of TagReference.create() in a deployed application - a code-review step that defenders should perform immediately. The Authentication Bypass tag from VulnCheck aligns with the unsafe-guard circumvention described. No EPSS score was provided in the input data, no KEV listing exists, and no public POC has been identified, so this is not a confirmed actively exploited issue at this time. Despite the 7.1 score, real-world risk is moderate-to-high specifically for CI/CD pipelines, repository management platforms, or code hosting tools that accept user-supplied tag reference names - these are the deployments most likely to surface this code path.

An attacker with low-privilege access to a web-based repository management platform (e.g., a self-hosted CI/CD tool built on GitPython) submits a tag creation request with a crafted reference value such as '--file=/etc/shadow' or '--file=/app/config/secrets.yaml'. GitPython passes this value positionally to the underlying git tag command, bypassing the unsafe guard; git interprets it as a file-read flag and embeds the file contents in the annotated tag message, which is returned to the attacker in the API response.