Reference page — cumulative record through Monday, October 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2021-20305

CVE-2021-20305HIGH

n/a nettle — A flaw was found in Nettle in versions before 3.7.2, where several Nettle signature verification functions (GOST DSA, EDDSA & ECDSA) resu…

  AV  AC  PR  UI  S  C  I  A   CVSS    EPSS   %ile   KEV
   N   H   N   N  U  H  H  H    8.1   .0174   77.4     —

AFFECTED
  Product  Versions        Fixed
  nettle   nettle 3.7.2 –  —

TIMELINE
  Dec 17  Reserved by redhat
  Apr 5   Published (CNA: redhat)
  Oct 14  ENRICHED — CVE-2021-20305 (nettle). Received CVSS 8.1 and CPE data from NVD.

CWE-787, CWE-327 · CNA: redhat · CVSS v3.1 · 7 references · NVD status: Modified

Description

A flaw was found in Nettle in versions before 3.7.2, where several Nettle signature verification functions (GOST DSA, EDDSA & ECDSA) result in the Elliptic Curve Cryptography point (ECC) multiply function being called with out-of-range scalers, possibly resulting in incorrect results. This flaw allows an attacker to force an invalid signature, causing an assertion failure or possible validation. The highest threat to this vulnerability is to confidentiality, integrity, as well as system availability.

Lifecycle

Complete event history — 3 events, chronological
Date	Event	Detail
December 17, 2020	Reserved	Reserved by redhat
April 5, 2021	Published	Published (CNA: redhat)
October 14, 2026	ENRICHED	ENRICHED — CVE-2021-20305 (nettle). Received CVSS 8.1 and CPE data from NVD.

Affected

Affected products and packages — 1 row
Vendor	Product / Package	Ecosystem	Version introduced	Fixed
n/a	nettle	—	nettle 3.7.2	—

Weaknesses

CWE-787 · CWE-327

References (7)

https://bugzilla.redhat.com/show_bug.cgi?id=1942533 [Issue Tracking, Patch, Third Party Advisory]
https://cert-portal.siemens.com/productcert/html/ssa-398330.html
https://lists.debian.org/debian-lts-announce/2021/09/msg00008.html [Mailing List, Third Party Advisory]
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MQKWVVMAIDAJ7YAA3VVO32BHLDOH2E63/
https://security.gentoo.org/glsa/202105-31 [Third Party Advisory]
https://security.netapp.com/advisory/ntap-20211022-0002/ [Third Party Advisory]
https://www.debian.org/security/2021/dsa-4933 [Third Party Advisory]

Authoritative record: CVE-2021-20305 at cve.org

Weaknesses: CWE-787 · CWE-327

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2021-20305 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Monday, October 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.