Description
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 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. This issue has been patched in version 1.0.3. There is no workaround for this issue.
Question to Ask Vendors:
- Can you confirm whether your systems are affected by CVE-2025-52556, and if so, what steps are you currently taking to mitigate this vulnerability?
- What is your estimated timeline for fully resolving CVE-2025-52556 in your products or services, and how will you communicate updates on this issue to us as your customer?
Recommended Actions:
- Check out the advisory links provided below.