CVE-2026-74752
CriticalCVSS 9.8Summary
In the Linux kernel's SCTP protocol, the COOKIE_ECHO state restoration does not properly validate AUTH fields (RANDOM, HMACS, CHUNKS) originating from peer-controlled cookie bytes. Forged lengths or identifiers can lead to out-of-bounds reads and even a write past a buffer, potentially enabling local privilege escalation.
Risk Assessment
A local attacker could exploit this vulnerability to escalate privileges or cause a system crash. Lack of cookie parameter validation may lead to kernel memory corruption.
Recommendation
Apply a Linux kernel update that includes the fix validating RANDOM, HMACS, and CHUNKS parameters at the cookie trust boundary before copying them into the association.
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: sctp: validate cookie AUTH state before use When cookie authentication is disabled, COOKIE_ECHO restores fixed-size AUTH fields directly from peer-controlled cookie bytes. A forged RANDOM length, HMAC list, or CHUNKS list can then reach association consumers with lengths or identifiers that were never validated against the local backing arrays. A forged RANDOM length can cause out-of-bounds reads during key-vector construction. A forged HMAC identifier also caused a 32-byte write past a zero-length AUTH chunk, providing a primitive for a local privilege escalation chain. Validate the cookie's RANDOM, HMACS, and CHUNKS parameters at the cookie trust boundary before copying them into the association. Reject invalid types, malformed lengths, unsupported HMAC identifiers, HMAC lists without SHA1, and forbidden chunk ids.