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CVE-2021-20232

31
FAUCET Score

CVE-2021-20232 is a critical use-after-free vulnerability in the gnutls library, specifically within the client_send_params function in lib/ext/pre_shared_key.c. This flaw affects various versions of Fedora, Red Hat Enterprise Linux, and gnutls itself. With a CVSS score of 9.8 (Critical), this vulnerability is remotely exploitable with low attack complexity and no user interaction required, potentially leading to complete compromise of confidentiality, integrity, and availability. The underlying issue is a CWE-416 (Use-After-Free). Currently, there is no evidence of active exploitation, and no public exploit code is available on platforms like Metasploit or ExploitDB. The vulnerability has received minimal community discussion and media coverage, indicating a low level of public awareness.

Impacted Technologies

VendorProductVersion(s)CPE
>= 3.6.3, < 3.7.1CPE matchmatch criteria
cpe:2.3:a:gnu:gnutls:*:*:*:*:*:*:*:*
8.0CPE matchmatch criteria
cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*
34CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

9.8CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
3.44%
Probability of exploitation in next 30 days
EPSS Percentile
87.8%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0344 is in the 80th percentile among its peer group of 36,897 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (11)

microsoftpatch availablevia msrc
Product: 19073-16823Fixed in: 3.6.14-5
microsoftpatch availablevia msrc
Product: cbl2 gnutls 3.6.14-5 on CBL Mariner 2.0Fixed in: 3.6.14-5
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: nettle-0:3.4.1-7.el8
View patch
redhatpatch availablevia nvd_reference
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: gnutls-0:3.6.16-4.el8
View patch
capnprotovendor investigatingvia llm_extracted
gcpvendor investigatingvia llm_extracted
hanwhavendor investigatingvia llm_extracted
kongvendor investigatingvia llm_extracted
openwrtvendor investigatingvia llm_extracted
proxmoxvendor investigatingvia llm_extracted

Vendor Advisories (8)

proxmoxllm-proxmox-202933dd58ce3ba3CRITICAL

ctrlX Multiple Vulnerabilities

Apr 23, 2021
kongllm-kong-7933c1edf7557da9CRITICAL

ctrlX Multiple Vulnerabilities

Apr 23, 2021
hanwhallm-hanwha-0b610f8bff10f748CRITICAL

ctrlX Multiple Vulnerabilities

Apr 23, 2021
capnprotollm-capnproto-5feb06313b602a85HIGH

ctrlX Multiple Vulnerabilities

Apr 23, 2021
openwrtllm-openwrt-b814c0e383a6a281CRITICAL

ctrlX Multiple Vulnerabilities

Apr 23, 2021
gcpllm-gcp-01a119d0ea3516faCRITICAL

ctrlX Multiple Vulnerabilities

Apr 23, 2021
redhatCVE-2021-20232Moderate

gnutls: Use after free in client_send_params in lib/ext/pre_shared_key.c

Mar 12, 2021
microsoft2021-Mar/CVE-2021-20232Critical

A flaw was found in gnutls. A use after free issue in client_send_params in lib/ext/pre_shared_key.c may lead to memory corruption and other potential consequences.

Mar 9, 2021

References

bugzilla.redhat.com / show_bug.cgi
Issue TrackingPatchThird Party Advisory
lists.apache.org / thread.html/r50661d6f0082709aad9a584431b59ec364f9974b63b07e0800230168%40%3Cissues.spark.apache.org%3E
lists.apache.org / thread.html/r5d4001031e7790d8c6396c499522b4ed2aab782da87b1a14184793bb%40%3Cissues.spark.apache.org%3E
lists.apache.org / thread.html/r5f88bed447742fcc5c47bf1c7be965ef450131914a6e1f85feba2779%40%3Cissues.spark.apache.org%3E
lists.apache.org / thread.html/r6ac143ba6dd98bd4bf6bf010d46e56e254056459721ba18822d611f7%40%3Cissues.spark.apache.org%3E
lists.apache.org / thread.html/r9cbc69e57276413788e90a6ee16c7c034ea4258d31935b70db2bd158%40%3Cissues.spark.apache.org%3E
lists.apache.org / thread.html/rcd70a4c88a47a75fd2d5f3ffb7cee8c2a18c713320bd90fdcb57495f%40%3Cissues.spark.apache.org%3E
lists.apache.org / thread.html/rf5e1256d870193def4a82ad89ab95e63943a313b5ff0d81aa87e4532%40%3Cissues.spark.apache.org%3E
lists.apache.org / thread.html/rfd5273d72d244178441e6904a2f2b41a3268f569e8092ea0b3b2bb20%40%3Cissues.spark.apache.org%3E
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/OSLAE6PP33A7VYRYMYMUVB3U6B26GZER
security.netapp.com / advisory/ntap-20210416-0005
Third Party Advisory
gnutls.org / security-new.html
Vendor Advisory