uv has differential in tar extraction with PAX headers
Impact
In versions 0.9.4 and earlier of uv, tar archives containing PAX headers with file size overrides were not handled properly. As a result, an attacker could contrive a source distribution (as a tar archive) that would extract differently when installed via uv versus other Python package installers.
The underlying parsing differential here originates with astral-tokio-tar, which disclosed this vulnerability as CVE-2025-62518.
In practice, the impact of this vulnerability is low: only source distributions can be formatted as tar archives, and source distributions execute arbitrary code at build/installation time by definition. Consequently, a parser differential in tar extraction is strictly less powerful than the capabilities already exposed to an attacker who has the ability to control source distributions.
However, this particular source of malleability in source distributions is unintentional and not operating by design, and therefore we consider it a vulnerability despite its overlap in capabilities with intended behavior.
Patches
Versions 0.9.5 and newer of uv address the vulnerability above. Users should upgrade to 0.9.5 or newer.
Workarounds
Users are advised to upgrade to version 0.9.5 or newer to address this advisory.
Users should experience no breaking changes as a result of the patch above.
References
- See CVE-2025-62518 for the corresponding advisory against astral-tokio-tar
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | uv | < 0.9.5 | 0.9.5 |
References
- https://github.com/astral-sh/uv/security/advisories/GHSA-w476-p2h3-79g9
- https://github.com/astral-sh/uv/pull/16387
- https://github.com/astral-sh/uv/commit/ae450662d1546e9853f67a8c61a506d3a892d963
- https://github.com/advisories/GHSA-j5gw-2vrg-8fgx
- https://github.com/astral-sh/uv
- https://github.com/astral-sh/uv/releases/tag/0.9.5
- Weakness (CWE)
CWE-843- Platform
- Python (PyPI)
- Package
uv- Disclosed
- 21.10.2025
- Updated
- 11.10.2026 12:19
Sources and licenses
OSV / GitHub Advisory Database - GHSA-w476-p2h3-79g9 - CC BY 4.0
Vulnerability history: uv
All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 7
- First → latest
- 08.2025 10.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Critical 1
- Medium 4
- Low 2
Disclosures per year
- 2025: 3
- 2026: 4
-
uv has differential in tar extraction with PAX headers this entry
Know which vulnerabilities affect your application
With the DockRay integration and software inventory enabled, DockRay checks reported component versions against known vulnerabilities and notifies you about confirmed matches. Coverage depends on the supported technology and available advisory data.