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TI-2025-32651 Aliases CVE-2025-52556GHSA-6qhv-4h7r-2g9m

rfc3161-client has insufficient verification for timestamp response signatures

Priority MEDIUM 47CWE-347Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Security bypass
Confidentiality · integrity · availability
High · High · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub. Impact type from CWE-347.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00169 6th percentileScored 2026-11-07
Fix Fixed rfc3161-client (trailofbits): 1.0.3rfc3161-client (PyPI): 1.0.3

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
trailofbitsrfc3161-clientbefore 1.0.31.0.3Patch availableCNA
—rfc3161-client (PyPI)before 1.0.31.0.3Patch availableGHSA-6qhv-4h7r-2g9m
  • rfc3161-client Vendortrailofbits Affected before 1.0.3 Fixed in 1.0.3 Patch available CNA
  • rfc3161-client (PyPI) Vendor— Affected before 1.0.3 Fixed in 1.0.3 Patch available GHSA-6qhv-4h7r-2g9m

Remediation

  • Fix · CNA rfc3161-client (trailofbits) Fixed in 1.0.3
  • Fix · GHSA-6qhv-4h7r-2g9m rfc3161-client (PyPI) Fixed in 1.0.3 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2025-52556
  2. 2026-10-03 Alias added: GHSA-6qhv-4h7r-2g9m

References

Advisory 1

Other 3

  • TI-2026-18173 Fickling vulnerable to detection bypass due to "builtins" blindness CVSS 4.0HIGH 8.9
  • TI-2026-18170 Fickling has Static Analysis Bypass via Incomplete Dangerous Module Blocklist CVSS 4.0HIGH 8.9
  • TI-2026-18169 Fickling vulnerable to use of ctypes and pydoc gadget chain to bypass detection CVSS 4.0HIGH 8.9
  • TI-2026-18168 Fickling Blocklist Bypass: cProfile.run() CVSS 4.0HIGH 8.9
  • TI-2026-18167 Fickling has a bypass via runpy.run_path() and runpy.run_module() CVSS 4.0HIGH 8.9
  • TI-2026-12265 Fickling MLAllowlist analysis pass rendered inoperative by shared mutable state in AnalysisContext.shorten_code() CVSS 3.1CRITICAL 9.8
See all 14 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences