The vulnerability CVE-2026-33845 involves an integer underflow in the GnuTLS DTLS handshake fragment reassembly process. Specifically, malformed DTLS fragments with zero length but non-zero offset cause an integer underflow during reassembly, resulting in an out-of-bounds read. This flaw is remotely exploitable without authentication and can lead to denial of service or information disclosure. Red Hat has issued security advisories and updates for GnuTLS packages in Red Hat Hardened Images and Red Hat Enterprise Linux 8 to fix this issue by adding checks to DTLS reassembly and correcting the underflow condition.

Successful exploitation of this vulnerability can cause denial of service by crashing the affected service or may lead to information disclosure due to out-of-bounds memory reads. The vulnerability is remotely exploitable without privileges or user interaction. The CVSS v3.1 base score is 7.5 (High), reflecting the network attack vector, low attack complexity, no privileges required, no user interaction, and an impact primarily on availability.

Red Hat has released updated GnuTLS packages that fix this vulnerability, including gnutls-3.8.13-1.hum1 for Red Hat Hardened Images and gnutls-3.6.16-8.el8_10.6 for Red Hat Enterprise Linux 8. Users should apply these official security updates promptly. The vendor advisory does not indicate any temporary workarounds or mitigations other than applying the patches. Patch status is confirmed by Red Hat advisories linked in the references.