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VulnerabilityPublished

CVE-2026-55174: shrec UltrafastSecp256k1 · Insufficient Verification of Data Authenticity

Affects shrec UltrafastSecp256k1Source CVE Database V5

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Not known to be exploited · CVSS 5.9 Medium : upgrade to 4.2.0 when convenient.

Data as of 14 Nov 2026, 20:44 UTC

CVSS 3.1 base score
5.9Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 4% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 4.2.0
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 30 Sep 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 14 Nov 2026.

What to do

Upgrade UltrafastSecp256k1 and shrec/UltrafastSecp256k1 to 4.2.0.

Affected software

ProductAffectedFixed in
shrecUltrafastSecp256k1Affected
  • <4.2.0
Fixed in
  • 4.2.0
GitHubshrec/UltrafastSecp256k1pkg:github/shrec/UltrafastSecp256k1Other threatsAffected
  • <4.2.0
Fixed in
  • 4.2.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Upgrade to UltrafastSecp256k1 version 4.2.0 or later, where this vulnerability has been patched. No other mitigation is indicated by the vendor advisory.

Description

CVE-2026-55174 is a medium severity vulnerability in the shrec UltrafastSecp256k1 library prior to version 4.2.0. The issue involves insufficient verification of data authenticity in the ECDSA adaptor pre-signature verification process, where forged adaptor pre-signatures with an "r" value not cryptographically bound to the adaptor point "T" can be accepted. This flaw has been addressed in version 4.2.0.

References

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