SB20260912100 - Use-after-free in Linux kernel nfsd
Published: September 12, 2026
Security Bulletin ID
SB20260912100
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Remote access
Highest impact
Data manipulation
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 vulnerability.
1) Use-after-free (CVE-ID: CVE-2026-89689)
CWE-ID: CWE-416 - Use After Free
CVSSv4: 6.3 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to cause memory corruption.
The vulnerability exists due to a use-after-free in nfsd4_sequence() when processing an NFSv4 SEQUENCE request during session slot reduction. A remote attacker can use a high-numbered session slot while acknowledging the slot reduction to cause memory corruption.
Active high-numbered slots can also be freed while in use by concurrent requests.
Remediation
Install update from vendor's website.