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 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 )
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-insensitive name constraints in certain cases. A remote attacker could possibly use this issue to bypass certificate validation, leading to a machine-in-the-middle attack. ( CVE-2026-3833 ) Joshua Rogers discovered that GnuTLS did not properly order DTLS packets with duplicate sequence numbers in certain cases. A remote attacker could possibly use this issue to cause GnuTLS to crash, resulting in a denial of service. ( CVE-2026-42009 ) Joshua Rogers discovered that GnuTLS did not properly handle usernames containing NUL characters in certain RSA-PSK configurations. A remote attacker could possibly use this issue to bypass authentication and gain unintended access to services. ( CVE-2026-42010 ) Haruto Kimura discovered that GnuTLS did not properly apply permitted name constraints in certain certificate validation paths. A remote attacker could possibly use this issue to bypass certificate validation, leading to a machine-in-the-middle attack. ( CVE-2026-42011 ) Oleh Konko discovered that GnuTLS incorrectly fell back to Common Name checks for certain URI and SRV subject alternative names. A remote attacker could possibly use this issue to bypass certificate validation, leading to a machine-in-the-middle attack. ( CVE-2026-42012 ) Haruto Kimura and Joshua Rogers discovered that GnuTLS incorrectly fell back to Common Name checks when subject alternative names were oversized. A remote attacker could possibly use this issue to bypass certificate validation, leading to a machine-in-the-middle attack. ( CVE-2026-42013 ) Luigino Camastra and Joshua Rogers discovered that GnuTLS had a use-after-free issue when changing PKCS#11 token security officer PINs in certain cases. An attacker could possibly use this issue to cause GnuTLS to crash, resulting in a denial of service, or execute arbitrary code. ( CVE-2026-42014 ) Zou Dikai discovered that GnuTLS did not properly validate PKCS#12 bag sizes in certain cases. An attacker could possibly use this issue to cause GnuTLS to crash, resulting in a denial of service, or execute arbitrary code. ( CVE-2026-42015 ) Joshua Rogers discovered that GnuTLS did not properly handle very short premaster secrets in certain RSA key exchange cases with PKCS#11-backed server keys. A remote attacker could possibly use this issue to obtain sensitive information. ( CVE-2026-5260 ) Doria Tang discovered that GnuTLS did not perform PKCS#7 padding checks in constant time in certain cases. A remote attacker could possibly use this issue to obtain sensitive information. This issue only affected Ubuntu 24.04 LTS, Ubuntu 25.10, and Ubuntu 26.04 LTS. ( CVE-2026-5419 )
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-insensitive name constraints in certain cases. A remote attacker could possibly use this issue to bypass certificate validation, leading to a machine-in-the-middle attack. ( CVE-2026-3833 )
Joshua Rogers discovered that GnuTLS did not properly order DTLS packets with duplicate sequence numbers in certain cases. A remote attacker could possibly use this issue to cause GnuTLS to crash, resulting in a denial of service. ( CVE-2026-42009 )
Joshua Rogers discovered that GnuTLS did not properly handle usernames containing NUL characters in certain RSA-PSK configurations. A remote attacker could possibly use this issue to bypass authentication and gain unintended access to services. ( CVE-2026-42010 )
Haruto Kimura discovered that GnuTLS did not properly apply permitted name constraints in certain certificate validation paths. A remote attacker could possibly use this issue to bypass certificate validation, leading to a machine-in-the-middle attack. ( CVE-2026-42011 )
Oleh Konko discovered that GnuTLS incorrectly fell back to Common Name checks for certain URI and SRV subject alternative names. A remote attacker could possibly use this issue to bypass certificate validation, leading to a machine-in-the-middle attack. ( CVE-2026-42012 )
Haruto Kimura and Joshua Rogers discovered that GnuTLS incorrectly fell back to Common Name checks when subject alternative names were oversized. A remote attacker could possibly use this issue to bypass certificate validation, leading to a machine-in-the-middle attack. ( CVE-2026-42013 )
Luigino Camastra and Joshua Rogers discovered that GnuTLS had a use-after-free issue when changing PKCS#11 token security officer PINs in certain cases. An attacker could possibly use this issue to cause GnuTLS to crash, resulting in a denial of service, or execute arbitrary code. ( CVE-2026-42014 )
Zou Dikai discovered that GnuTLS did not properly validate PKCS#12 bag sizes in certain cases. An attacker could possibly use this issue to cause GnuTLS to crash, resulting in a denial of service, or execute arbitrary code. ( CVE-2026-42015 )
Joshua Rogers discovered that GnuTLS did not properly handle very short premaster secrets in certain RSA key exchange cases with PKCS#11-backed server keys. A remote attacker could possibly use this issue to obtain sensitive information. ( CVE-2026-5260 )
Doria Tang discovered that GnuTLS did not perform PKCS#7 padding checks in constant time in certain cases. A remote attacker could possibly use this issue to obtain sensitive information. This issue only affected Ubuntu 24.04 LTS, Ubuntu 25.10, and Ubuntu 26.04 LTS. ( CVE-2026-5419 )
In general, a standard system update will make all the necessary changes.
The problem can be corrected by updating your system to the following package versions:
Ubuntu Pro provides ten-year security coverage to 25,000+ packages in Main and Universe repositories, and it is free for up to five machines.
The full story
This article is one source in a clustered incident — the cluster page carries the summary, timeline and every other outlet covering it.
