Ubuntu 26.04 GnuTLS Important Denial Of Service USN-8284-1

ubuntu

May 20, 2026

Several security issues were fixed in GnuTLS.

Summary

Several security issues were fixed in GnuTLS.

Software Description:

- gnutls28: GNU TLS library

Details:

Joshua Rogers discovered that GnuTLS did not properly handle malformed

DTLS handshake fragments in certain cases. A remote attacker could

possibly use this issue to obtain sensitive information, or cause a

denial of service. (CVE-2026-33845)

Haruto Kimura, Oscar Reparaz, and Zou Dikai discovered that GnuTLS did

not properly validate DTLS handshake fragment lengths in certain cases. A

remote attacker could possibly use this issue to cause GnuTLS to crash,

resulting in a denial of service, or execute arbitrary code.

(CVE-2026-33846)

Oleh Konko and Joshua Rogers discovered that GnuTLS did not properly

validate OCSP responses in certain cases. A remote attacker could

possibly use this issue to bypass certificate revocation checks, leading

to a machine-in-the-middle attack. (CVE-2026-3832)

Oleh Konko and Joshua Rogers discovered that GnuTLS did not properly

handle case-insensit...

Read the Full Advisory

Topics Covered

security advisory denial of service Ubuntu important gnutls sensitive information

Update Instructions

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 26.04 LTS
  libgnutls30t64                  3.8.12-2ubuntu1.1

Ubuntu 25.10
  libgnutls30t64                  3.8.9-3ubuntu2.2

Ubuntu 24.04 LTS
  libgnutls30t64                  3.8.3-1.1ubuntu3.6

Ubuntu 22.04 LTS
  libgnutls30                     3.7.3-4ubuntu1.9

In general, a standard system update will make all the necessary changes.