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GHSA-6qhv-4h7r-2g9m

rfc3161-client has insufficient verification for timestamp response signatures

Source: GitHub Advisory Database (reviewed) Critical CVE-2025-52556

Packages

EcosystemPackageAffectedFixed in
PyPI rfc3161-client < 1.0.3 1.0.3

Details

As written in the advisory (Markdown source, shown as plain text).

### Impact `rfc3161-client` 1.0.2 and earlier contain a flaw in their timestamp response signature verification logic. In particular, it performs chain verification against the TSR's embedded certificates up to the trusted root(s), but fails to verify the TSR's own signature against the timestamping leaf certificates. Consequently, vulnerable versions perform insufficient signature validation to properly consider a TSR verified, as the attacker can introduce _any_ TSR signature so long as the embedded leaf chains up to some root TSA. ### Patches Users should immediately upgrade to `rfc3161-client` 1.0.3 or later. ### Workarounds There is no workaround possible. Users should immediately upgrade to a fixed version.

References

External links from the advisory. They lead to third-party sites.