Out-of-bounds read in GnuTLS - CVE-2026-5260
Published: April 30, 2026
Vulnerability identifier: #VU128577
CSH Severity: Medium
CVSSv4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-5260
CWE-ID: CWE-125
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerable software:
GnuTLS
GnuTLS
Software vendor:
GnuTLS
GnuTLS
Description
The vulnerability allows a remote attacker to disclose sensitive information.
The vulnerability exists due to out-of-bounds read in RSA key exchange handling when processing an extremely short premaster secret from a client for a server using an RSA key backed by a PKCS#11 token. A remote attacker can send a specially crafted premaster secret to disclose sensitive information.
Only servers using an RSA key backed by a PKCS#11 token are vulnerable.
Remediation
Install security update from vendor's website.