SB2026062686 - Time-of-check Time-of-use (TOCTOU) Race Condition in Linux kernel xdp

Description

This security bulletin contains information about 1 vulnerability.

1) Time-of-check Time-of-use (TOCTOU) Race Condition (CVE-ID: CVE-2026-53250)

CWE-ID: CWE-367 - Time-of-check Time-of-use (TOCTOU) Race Condition

CVSSv4: 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

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.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/0dfe05b938435892875e07771170051346412df9
• https://git.kernel.org/stable/c/22ba97ea9cc1f63a0d0244fae38057ed452b6ac7
• https://git.kernel.org/stable/c/bfdfd2706d5fb2cd496a1506e680daf979309c8b