CVE-2026-55174

MEDIUMPre-NVD 5.95.9—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.9 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.1% (3rd percentile of EPSS-scored CVEs). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Trending — 3 sources updated this weekElevated
5.9EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.1%CVSS: 5.9Exploit: Elevated riskExposed services: Not assessed

A fix is available — apply it.

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.

CVSS v3
5.9
EG Score
5.9MEDIUMmedium confidence
EG Risk
43
EG Risk 43/100CISA SSVC

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity59% × 45%
Exploitation40% × 40%
Automatability0% × 15%
CISA SSVC: Track at low or medium mission impact; Track* at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.1%
EPSS %ILE
3rd
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Track* at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines.

Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

September 30, 2026

Last Modified

September 30, 2026

Advisory Details (4)

Auto-updated Sep 30, 2026
🔬 Proof of concept available. Patch available. Sources: github_commit, github_release, github.
github Patch Available🟡 PoC Available

ECDSA adaptor verification accepts non-adaptable pre-signatures due to missing DLEQ binding · Advisory · shrec/UltrafastSecp256k1 · GitHub

https://github.com/shrec/UltrafastSecp256k1/security/advisories/GHSA-c7q2-gv3g-rgxm
github_release Patch Available

UltrafastSecp256k1 v4.2.1

Patch available: shrec/UltrafastSecp256k1 v4.2.1

https://github.com/shrec/UltrafastSecp256k1/releases/tag/v4.2.1
github_release Patch Available

v4.2.0

Patch available: shrec/UltrafastSecp256k1 v4.2.0 (pre-release)

https://github.com/shrec/UltrafastSecp256k1/releases/tag/v4.2.0
github_commit

commit 5478ef566c6a (shrec/UltrafastSecp256k1)

Fix landed in shrec/UltrafastSecp256k1 commit 5478ef566c6a — awaiting tagged release

https://github.com/shrec/UltrafastSecp256k1/commit/5478ef566c6af91b48a45c0c61f161f5b1071981

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 11× in last 7d / 11× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-10-03 18:02 UTCEG score recompute
  2. 2026-10-03 14:26 UTCEPSS rescore
  3. 2026-10-02 18:47 UTCEG score recompute
  4. 2026-10-02 17:56 UTCEPSS rescore
  5. 2026-10-01 19:50 UTCEPSS rescore
  6. 2026-10-01 19:33 UTCEG score recompute
  7. 2026-09-30 20:01 UTCEG score recompute
  8. 2026-09-30 19:56 UTCEG score recompute
  9. 2026-09-30 16:21 UTCEG score recompute
  10. 2026-09-30 15:52 UTCEG score recompute
  11. 2026-09-30 15:51 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-55174?
CVE-2026-55174 is a medium vulnerability published on September 30, 2026. 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"…
When was CVE-2026-55174 disclosed?
CVE-2026-55174 was first published on September 30, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-55174 actively exploited?
CVE-2026-55174 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.1% probability of exploitation in the next 30 days (3rd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-55174?
CVE-2026-55174 has a CVSS base score of 5.9 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-55174?
A fix for CVE-2026-55174 is available: update to the fixed version the vendor names in its advisory.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2026-55174

Explore →

Is Your Infrastructure Affected by CVE-2026-55174?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Book a Demo →Browse All CVEs