CVE-2021-20231: fedoraproject fedora Use After Free
CVSS: 9.8v3.1CriticalModified
AliasesALPINE-CVE-2021-20231UBUNTU-CVE-2021-20231DEBIAN-CVE-2021-20231CGA-rjw7-qg6m-wh9gCGA-vc43-64pc-5mhv
Published 12-03-2021Last modified 14-10-2026
Vulnerability summary
CVE-2021-20231 is a critical (CVSS 9.8) Use After Free vulnerability in fedoraproject fedora. EPSS estimates a 3.80% chance of exploitation in the next 30 days, higher than 89.8% of scored vulnerabilities. 1 public exploit is recorded.
CVSS score
9.8/10
010
Critical · v3.1 (NVD)EPSS score
3.80%
0%100%
Low · +0.04 pp in 30 daysKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits1reference
Advisory lineage
Upstream 0 · Downstream 6 · Related 6Timeline
- 12-03-2021PublishedVulnerability first disclosed.
- 14-10-2026Last modifiedVulnerability information updated.
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.
CVSS metrics
7 scores · 6 sources · 2 versionsCritical 9.8Preferred score · NVD (NIST)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HSourcesAll 6 agree
- OSV · AlpineEcosystem advisory · calculated9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- OSV · UbuntuEcosystem advisory · calculated9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- OSV · DebianEcosystem advisory · calculated9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- OSV · WolfiEcosystem advisory · calculated9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- OSV · ChainguardEcosystem advisory · calculated9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
High 7.5Preferred score · NVD (NIST)
AV:N/AC:L/Au:N/C:P/I:P/A:PSourcesSingle source
EPSS trend
Probability
3.80%
Chance of exploitation in the next 30 days
Percentile
90%
Versus all other CVEs
30-day change
+0.04 pp
From 3.75% on 18-09-2026
18-09-202618-10-2026
EPSS score3.80%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
1 foundExploit Reference (gnutls.org)
Maturity: unknown
Weaknesses
CWE · root causeAffected systems
Netapp2 products
Alpine1 product
- gnutls≥ 3.6.3, < 3.6.15-r1 | ≥ 3.6.3, < 3.7.1-r0
Chainguard1 product
- gnutlsAll versions (No fix recorded)
Debian1 product
- gnutls28< 3.7.1-1
Fedoraproject1 product
- fedoraEOL34
Gnu1 product
- gnutls≥ 3.6.3, < 3.7.1
Redhat1 product
Ubuntu1 product
- gnutls28< 3.6.13-2ubuntu1.6
Wolfi1 product
- gnutlsAll versions (No fix recorded)
9 vendors · 10 products
References
19 links- bugzilla.redhat.com/show_bug.cgi?id=1922276X Refsource MISCFIXIssue TrackingPatchThird Party Advisory
