Time-of-check Time-of-use (TOCTOU) Race Condition in Linux kernel - CVE-2026-53250
Published: June 26, 2026
Vulnerability identifier: #VU135520
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-53250
CWE-ID: CWE-367
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vendor: Linux Foundation
Affected software:
Linux kernel
Linux kernel
Detailed vulnerability description
The vulnerability allows a local user to cause out-of-bounds memory access.
The vulnerability exists due to a time-of-check time-of-use race condition in xsk_skb_metadata() when processing transmit metadata from a userspace-writable UMEM buffer. A local user can race to overwrite csum_start and csum_offset between validation and assignment to cause out-of-bounds memory access.
The issue occurs during checksum computation in the transmit path.
How to mitigate CVE-2026-53250
Install security update from vendor's repository.