astral-tokio-tar has a PAX Header Desynchronization issueGHSA-3cv2-h65g-fgmm
GHSA-3cv2-h65g-fgmm is a security vulnerability in astral-tokio-tar. A fix is available for astral-tokio-tar — see the affected versions and patch details below.
Real-World Exposure
astral-tokio-tarReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects crates.io packages — download data is not available via public APIs for these ecosystems.
Description
Impact
Versions of astral-tokio-tar prior to 0.6.2 contain a PAX header interpretation bug that allows manipulated entries to be made selectively visible or invisible during extraction with astral-tokio-tar versus other tar implementations. An attacker could use this differential to smuggle unexpected files onto a victim's filesystem.
Details
When a tar stream contains multiple "header" entries prior to a file entry, astral-tokio-tar applies the PAX header (x) to the next entry in the stream, regardless of type. For example, a stream of x -> L -> file (PAX, GNU longname, file) would result in x's extensions being applied to L rather than to file.
Per POSIX pax, this is incorrect: a PAX header always applies to a file entry, not any intermediary entries. See the "pax Header Block" section for the specific prescription there.
As a result of this, an attacker can contrive a tar containing a sequence of tar headers such that astral-tokio-tar applies the PAX header's size extension to the next header in sequence, effectively desynchronizing the stream and enabling astral-tokio-tar specific skippage/extraction of members. In other words, a file can be contrived to extract differently on astral-tokio-tar than on other tar parsers.
Patches
Versions 0.6.2 and newer of astral-tokio-tar address this differential.
Workarounds
Users are advised to upgrade to version 0.6.1 or newer to address this advisory.
There is no workaround other than upgrading. Users should experience no breaking changes as a result of the upgrade.
Resources
- GHSA-j5gw-2vrg-8fgx is a similar PAX desynchronization bug
- GHSA-fp55-jw48-c537 is another similar PAX desynchronization bug
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | astral-tokio-tar | all versions | 0.6.2cargo update -p astral-tokio-tar --precise 0.6.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for astral-tokio-tar, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update astral-tokio-tar to 0.6.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-3cv2-h65g-fgmm 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.
Frequently Asked Questions
Is GHSA-3cv2-h65g-fgmm in your dependencies?
Find it across crates.io, including transitive dependencies.