The gnutls library in Red Hat Enterprise Linux 10 contains multiple vulnerabilities, including a heap buffer overflow leading to denial of service during DTLS handshake fragment reassembly (CVE-2026-33846), a qsort comparator issue in DTLS reassembly (CVE-2026-42009), crashing on underflow with DTLS datagrams (CVE-2026-33845), RSA-PSK identity truncation causing authentication bypass (CVE-2026-42010), and incorrect handling of name constraints causing security bypass (CVE-2026-3833, CVE-2026-42011). These issues impact the cryptographic operations of GnuTLS, which implements SSL, TLS, and DTLS protocols. Red Hat has rated the update as having a moderate security impact and has issued patches in advisory RHSA-2026:20613 for Red Hat Enterprise Linux 10 across multiple architectures.

The vulnerabilities could allow denial of service conditions via heap buffer overflow and DTLS packet reordering, authentication bypass through RSA-PSK identity truncation, and security bypass due to improper name constraint handling. Confidentiality impact is limited (low), with no integrity or availability impacts explicitly stated beyond denial of service. The issues affect the cryptographic protocol implementations, potentially undermining secure communications if exploited.

Red Hat has released an official security update for gnutls in Red Hat Enterprise Linux 10 addressing these vulnerabilities. Users should apply the update as per Red Hat advisory RHSA-2026:20613 after ensuring all previous errata are applied. Detailed update instructions are available at https://access.redhat.com/articles/11258. No additional mitigations are indicated beyond applying the official patch.