SB20260912234 - Integer underflow in Linux kernel sunrpc

Description

This security bulletin contains information about 1 vulnerability.

1) Integer underflow (CVE-ID: CVE-2026-89551)

CWE-ID: CWE-191 - Integer underflow

CVSSv4: 0 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:N/SA:N]

The vulnerability allows a remote attacker to cause downstream XDR decoders to use an incorrect stream bound.

The vulnerability exists due to an integer underflow in xdr_buf_trim() when processing GSS Kerberos v2 data whose recorded buffer length is smaller than the associated I/O vector lengths. A remote attacker can cause xdr_buf_trim() to consume more bytes than buf->len records to cause downstream XDR decoders to use an incorrect stream bound.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/3f491306dcb673ff5e78e1044ba450c58978774e
• https://git.kernel.org/stable/c/85e9602650e9df07190abe817cee3b4d9bc3df17
• https://git.kernel.org/stable/c/ad0cce80d4af2f74674e8b635d97aa3880e83da8
• https://git.kernel.org/stable/c/e6267cccd7b05cc514e57f2160aa8db85f5c2701