Linux Kernel MPTCP Flaw Can Drop Retransmitted Packets and Cause DoS
Vulnerability Disclosure · 2 sources · Updated 2mo ago · First seen Jul 8, 2024
CVE-2024-26826 is a moderate-severity Linux kernel flaw in Multipath TCP (MPTCP) that can cause unacknowledged data to be lost when a subflow becomes stale. An invalid optimization invoked a TCP-specific retransmission-queue helper on an MPTCP socket; following a TCP fast-path variable reorganization, the check could skip required data reinjection, creating a denial-of-service condition through lost retransmitted packets. The defect was introduced in kernel version 5.15.
The issue is fixed in stable kernels 5.15.149, 6.1.79, 6.6.18, 6.7.6, and 6.8 and later. Red Hat rated the vulnerability CVSS 3.1 5.5 (moderate), citing local low-complexity exploitation with low privileges and high availability impact, and released updated kernel packages for affected Red Hat Enterprise Linux 8 and 9 systems; RHEL 6 is not affected. Organizations should deploy current vendor kernel updates rather than cherry-picking the individual patch.
