Skip to main content
No exploitation reportedFix available

CVE-2021-20231

No exploitation reported by the sources we read.

  • Published2021-03-12
  • WeaknessCWE-416

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC
  1. 2021-03-1219:15CVE publishedNVD

Versions per branch

NVD
Fedoraproject fedora
BranchAffectedFixed in
34.x= 34no fix published
Gnu gnutls
BranchAffectedFixed in
3.x≥ 3.6.3, < 3.7.13.7.1
Netapp active iq unified manager
BranchAffectedFixed in
—all versionsno fix published

2 more products in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • gnutlsWolfiall versions · fixed in 0
  • gnutlsSUSE:Manager Server 4.0all versions · fixed in 3.6.7-6.40.2
  • gnutlsSUSE:Manager Retail Branch Server 4.0all versions · fixed in 3.6.7-6.40.2
  • gnutlsSUSE:Manager Proxy 4.0all versions · fixed in 3.6.7-6.40.2
  • gnutlsSUSE:Linux Enterprise Server for SAP Applications 15 SP1all versions · fixed in 3.6.7-6.40.2
  • gnutlsSUSE:Linux Enterprise Server for SAP Applications 15all versions · fixed in 3.6.7-6.40.2
  • gnutlsSUSE:Linux Enterprise Server 15-LTSSall versions · fixed in 3.6.7-6.40.2
  • gnutlsSUSE:Linux Enterprise Server 15 SP1-LTSSall versions · fixed in 3.6.7-6.40.2

43 more package ranges on OSV.dev

Vendor advisories

  • CVE-2021-20231 Red Hat Product Security106 products fixed

    gnutls: Use after free in client key_share extension

  • ICSA-23-348-10 CISA5 known affected

    Siemens SIMATIC S7-1500

    SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) · SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) · SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) · +2 more

  • SSA-398330 Siemens ProductCERT5 known affected

    SSA-398330: Vulnerabilities in the additional GNU/Linux subsystem of the SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP >= V3.1.0 and < V3.1.5

    SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) >= V3.1.0 < V3.1.5 · SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) >= V3.1.0 < V3.1.5 · SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) >= V3.1.0 < V3.1.5 · +2 more

  • RHSA-2021:4451 Red Hat Product Security106 products fixed

    Red Hat Security Advisory: gnutls and nettle security, bug fix, and enhancement update

Full record on NVD

Fix

  1. Vendor fix CISA ICSA-23-348-10 · 5 productsUpdate to V3.1.5 or later version
  2. Vendor fix Siemens ProductCERT SSA-398330 · 1 productUpdate to V3.1.5 or later version
  3. Vendor fix Red Hat Product Security RHSA-2021:4451 · 106 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
  4. Mitigation from the vendor CISA ICSA-23-348-10 · 5 productsOnly build and run applications from trusted sources.

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published
2021-03-12
Last Modified
2026-10-14
NVD status
Modified
GitHub Advisory
GHSA-mqq9-xchh-h97q

Frequently asked questions

What is CVE-2021-20231?

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.

Is CVE-2021-20231 actively exploited?

Active exploitation of CVE-2021-20231 has not been confirmed. Its EPSS score was 3.7% on 2026-11-08, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-20231?

CVE-2021-20231 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Running gnutls? Hear about its next vulnerability

Surveillance reads the versions in your stack — a domain, a lockfile or a list — checks each CVE against the ranges its sources publish, and alerts you when one you run is exploited or enters CISA KEV. A version it cannot read stays « version not verified ».

Get alerts for this productCISA KEV additions, November 2026Search CVEs

No credit card required · No monthly cap on website lookups · 250 API requests/month

Go further

Related vulnerabilities

Same product first, then the same vendor advisory and the same publication week.

Back to CVE Database

Sources for this record