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-2021-20231

CVE-2021-20231CRITICAL

n/a gnutls — A flaw was found in gnutls.

  AV  AC  PR  UI  S  C  I  A   CVSS    EPSS   %ile   KEV
   N   L   N   N  U  H  H  H    9.8   .0380   89.9     —

AFFECTED
  Product  Versions        Fixed
  gnutls   gnutls 3.7.1 –  —

TIMELINE
  Dec 17  Reserved by redhat
  Mar 12  Published (CNA: redhat)
  Oct 14  ENRICHED — CVE-2021-20231 (gnutls). Received CVSS 9.8 and CPE data from NVD.
  Oct 14  EXPLOIT PUBLISHED — CVE-2021-20231 (gnutls). Public exploit reference added.

CWE-416 · CNA: redhat · CVSS v3.1 · 13 references · NVD status: Modified

Description

A flaw was found in gnutls. A use after free issue in client sending key_share extension may lead to memory corruption and other consequences.

Lifecycle

Complete event history — 4 events, chronological
Date	Event	Detail
December 17, 2020	Reserved	Reserved by redhat
March 12, 2021	Published	Published (CNA: redhat)
October 14, 2026	ENRICHED	ENRICHED — CVE-2021-20231 (gnutls). Received CVSS 9.8 and CPE data from NVD.
October 14, 2026	EXPLOIT PUBLISHED	EXPLOIT PUBLISHED — CVE-2021-20231 (gnutls). Public exploit reference added.

Affected

Affected products and packages — 1 row
Vendor	Product / Package	Ecosystem	Version introduced	Fixed
n/a	gnutls	—	gnutls 3.7.1	—

Weaknesses

CWE-416

References (13)

Authoritative record: CVE-2021-20231 at cve.org

Weaknesses: CWE-416

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2021-20231 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.