CVE-2026-33845

Publication date 30 April 2026

Last updated 6 July 2026

Ubuntu priority

Cvss 3 Severity Score

Description

A flaw in GnuTLS DTLS handshake parsing allows malformed fragments with zero length and non-zero offset, leading to an integer underflow during reassembly and resulting in an out-of-bounds read. This issue is remotely exploitable and may cause information disclosure or denial of service.

Status

Show unmaintained releases

Package	Ubuntu Release	Status
gnutls28	26.04 LTS resolute	Fixed 3.8.12-2ubuntu1.1
	25.10 questing	Fixed 3.8.9-3ubuntu2.2
	24.04 LTS noble	Fixed 3.8.3-1.1ubuntu3.6
	22.04 LTS jammy	Fixed 3.7.3-4ubuntu1.9
	20.04 LTS focal	Fixed 3.6.13-2ubuntu1.12+esm2
	18.04 LTS bionic	Not affected
	16.04 LTS xenial	Not affected

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Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package	Patch details
gnutls28	Upstream: e5b72c5

Severity score breakdown

CVSS version: CVSS v3.0

Base score 7.5 · High

Base metrics

Parameter	Value
Attack vector	Network
Attack complexity	Low
Privileges required	None
User interaction	None
Scope	Unchanged
Confidentiality impact	None
Integrity impact	None
Availability impact	High

Scores

Parameter	Value
Base score	7.5 · High
Exploitability score	-
Impact score	-

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

References

Related Ubuntu Security Notices (USN)

USN-8284-1
GnuTLS vulnerabilities
20 May 2026

USN-8502-1
GnuTLS vulnerabilities
6 July 2026