HOMEVULNERABILITIESCVE-2021-20231
CRITICAL

CVE-2021-20231

CWE-416Published: March 12, 2021· Updated: Jun 17, 2026

9.8
CVSS v3.1

Official 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.

NVD Source

Technical Analysis

CVE-2021-20231 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 9.8.

From a weakness classification perspective (CWE-416): Use-after-free vulnerabilities involve accessing memory after it has been freed, often enabling arbitrary code execution.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected Vendors & Products

Fedora1 product(s)
fedora
gnu1 product(s)
gnutls
netapp2 product(s)
active iq unified managere-series performance analyzer
Red Hat1 product(s)
enterprise linux
Source: NVD CPE · 5 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

All References (24)

https://bugzilla.redhat.com/show_bug.cgi?id=1922276Issue Tracking · Patch · Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=1922276Issue Tracking · Patch · Third Party Advisory

Quick Facts

CVE IDCVE-2021-20231
CVSS Score9.8 / 10
SeverityCRITICAL
WeaknessCWE-416
CISA KEVNo
Affected4 vendor(s)
PublishedMar 12, 2021

Related CVEs (CWE-416)

Recommended Actions

  • Apply vendor patches immediately
  • Monitor CVE-2021-20231 in threat intel feeds
  • Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWatch. CVE data is provided under the NVD usage policy.