CVE-2026-5260

A flaw was found in libgnutls. A remote attacker, by sending an extremely short premaster secret during an RSA key exchange to a server using an RSA key backed by a PKCS#11 token, could trigger a short heap overread. This memory corruption vulnerability could lead to information disclosure.

Red Hat Product Security rates this vulnerability as Moderate severity because exploitation requires a specialized server setup where RSA key exchange is negotiated using a private key hosted on a PKCS#11 token. In standard Red Hat Enterprise Linux deployments, system-wide crypto policies prioritize forward-secret (EC)DHE cipher suites, and PKCS#11 hardware tokens are not configured by default. Furthermore, the issue only triggers a bounded heap overread, resulting in limited information disclosure rather than arbitrary code execution.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.