Use-after-free in Linux kernel - CVE-2026-98374
Published: October 8, 2026
Vulnerability identifier: #VU153951
CSH Severity: Low
CVSS v4: 5.7 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-98374
CWE-ID: CWE-416
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to use-after-free in tcp_send_synack() when replacing a cloned SYN socket buffer in the retransmit queue without updating the retransmission hint. A local user can initiate a TCP Fast Open connection using sendmsg(MSG_FASTOPEN) and supply an ICMP fragmentation-needed message to cause a denial of service.
Exploitation requires a simultaneous open after the retransmission hint has been armed.
Affected software
Linux kernel
How to mitigate CVE-2026-98374
Install security update from vendor's repository.
Linux kernel - update to 7.0 rc3
External References
- https://git.kernel.org/stable/c/0f87720c7e4bcab07c24888b3cf12bfe857bb90e
- https://git.kernel.org/stable/c/631aa4cb45099f09e9385dd786bd291c6270bfc4
- https://git.kernel.org/stable/c/71d45049b0d631dfdbf3c65305f7fca676de023b
- https://git.kernel.org/stable/c/c5b4da1f403a658c1c19766be2b426003ada419f
- https://git.kernel.org/stable/c/e3ea71cb1408a013ed4e8a757b815f1a919324bd
- https://git.kernel.org/stable/c/fad6d429651e748365e93ca54645accc212f0018
- https://git.kernel.org/stable/c/fe99bbeee5c5dbd3abc30721a8079ced59649d97