SB20260507253 - Improper input validation in Linux kernel xfrm

Description

This security bulletin contains information about 1 vulnerability.

1) Improper input validation (CVE-ID: CVE-2026-43107)

CWE-ID: CWE-20 - Improper input validation

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 a denial of service.

The vulnerability exists due to improper input validation in xfrm_get_ae() and xfrm_aevent_msgsize() when handling malformed netlink interactions for xfrm aevent messages. A local user can send a malformed netlink interaction to cause a denial of service.

The issue is triggered for states with if_id set, where the reply skb size calculation does not account for the XFRMA_IF_ID attribute.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/2c41283d94af943a05f7f2cc1a01f0c872f3cf43
• https://git.kernel.org/stable/c/58e5735d1a5373652f405a0c16e54ac04aaab0ad
• https://git.kernel.org/stable/c/7081d46d32312f1a31f0e0e99c6835a394037599
• https://git.kernel.org/stable/c/e62e322ea20be78e346e4b49f9a6b9f03313af4c