PYSEC-2026-525 rfc3161-client has insufficient verification for timestamp response signatures

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 roots, but fails to verify the TSR's own signature against the timestamping leaf...

CVE-2025-52556 rfc3161-client has insufficient verification for timestamp response signatures

rfc3161-client is a Python library implementing the Time-Stamp Protocol TSP described in RFC 3161. Prior to version 1.0.3, there is a flaw in the timestamp response signature verification logic. In particular, chain verification is performed against the TSR's embedded certificates up to the trust...