CVE-2026-55174 json
UltrafastSecp256k1: ECDSA adaptor verification accepts non-adaptable pre-signatures due to missing DLEQ binding
published 2026-09-30 39 d ago modified 2026-09-30 39 d ago also EUVD-2026-90188
- cvss
- 5.9
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.1%
- EPSS 0.1% chance of exploitation in 30 days, percentile 4%
- public exploits
- 0
- none known
Summary
UltrafastSecp256k1 is a high-performance, multi-backend secp256k1 engine with reproducible audit evidence, compatibility shims, and profile-based review scopes. Prior to version 4.2.0, UltrafastSecp256k1's ECDSA adaptor pre-signature verification accepts forged adaptor pre-signatures whose "r" value is not cryptographically bound to the adaptor point "T". This issue has been patched in version 4.2.0.
Patch / fix
CISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- no
- Technical impact
- partial
- Assessed
- 39 d ago
Exploit prediction
0.15% chance of exploitation in the next 30 days, higher than 4% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- github.com https://github.com/shrec/UltrafastSecp256k1/security/advisories/GHSA-c7q2-gv3g-rgxm referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 5.9 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N |
Affected products
- shrec UltrafastSecp256k1
Classification
References
Sources
- CVE List CVE-2026-55174
- NVD CVE-2026-55174
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