CVE-2025-52556 json
rfc3161-client has insufficient verification for timestamp response signatures
published last yr. modified 3mo ago also EUVD-2025-18798 , GHSA-6qhv-4h7r-2g9m , PYSEC-2026-525
- cvss
- 9.3
- version 4.0, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.2%
- EPSS 0.2% chance of exploitation in 30 days, percentile 6%
- public exploits
- 0
- none known
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.
Patch / fix
- pypi rfc3161-client 1.0.3
- trailofbits rfc3161-client 1.0.3
- python-rfc3161-client openSUSE Tumbleweed 1.0.3-1.1
opensuse advisories openSUSE-SU-2025:15282-1
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Check with FencerCISA SSVC
- Exploitation
- none
- Automatable
- yes
- Technical impact
- total
- Assessed
- last yr.
Exploit prediction
0.17% chance of exploitation in the next 30 days, higher than 6% of all scored CVEs (FIRST EPSS, 2026-11-09).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 9.3 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N |
| CNA | 4.0 | 9.3 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| pypi | rfc3161-client | <1.0.3 |
1.0.3 |
Affected products
- trailofbits rfc3161-client
Classification
- Weakness
-
- CWE-347 Improper Verification of Cryptographic Signature
References
-
github.com
/trailofbits/rfc3161-client/commit/724a184f953e3f171f85cb223871172b41b0d0dc
web
-
github.com
/trailofbits/rfc3161-client/security/advisories/GHSA-6qhv-4h7r-2g9m
web
-
nvd.nist.gov
/vuln/detail/CVE-2025-52556
advisory
-
github.com
/trailofbits/rfc3161-client
package
-
pypi.org
/project/rfc3161-client
package
-
github.com
/advisories/GHSA-6qhv-4h7r-2g9m
advisory
Sources
- CVE List CVE-2025-52556
- GitHub Advisory GHSA-6qhv-4h7r-2g9m
- NVD CVE-2025-52556
- OSV PYSEC-2026-525
Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.
CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.