SB20260815291 - Out-of-bounds write in Linux kernel netfilter

Description

This security bulletin contains information about 1 vulnerability.

1) Out-of-bounds write (CVE-ID: CVE-2026-72423)

CWE-ID: CWE-787 - Out-of-bounds write

CVSSv4: 6.8 [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]

The vulnerability allows a local user to cause memory corruption.

The vulnerability exists due to an out-of-bounds write in conntrack lookup and allocation bpf kfunc wrappers in net/netfilter/nf_conntrack_bpf.c when handling an opts pointer with an invalid size smaller than the end of opts->error. A local user can supply a crafted opts pointer and opts__sz value to cause memory corruption.

Exploitation requires invoking the affected bpf conntrack lookup or allocation helpers with an invalid opts size.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/6f6183a39533d727deaa5061cadae6dd9e6744d0
• https://git.kernel.org/stable/c/dd74c80203842a21b2ebb9f70d1260d9aa20fa05