SB20260720395 - NULL pointer dereference in Linux kernel tty serial driver
Published: July 20, 2026
Security Bulletin ID
SB20260720395
CSH Severity
Low
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Local access
Highest impact
Denial of service
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 vulnerability.
1) NULL pointer dereference (CVE-ID: CVE-2026-63876)
CWE-ID: CWE-476 - NULL Pointer Dereference
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 a denial of service.
The vulnerability exists due to a null pointer dereference in the zs serial driver during serial port initialization when initializing the first serial port. A local user can trigger driver initialization to cause a denial of service.
The issue can crash the kernel during system bootstrap on affected DECstation systems.
Remediation
Install update from vendor's website.
References
- https://git.kernel.org/stable/c/237dc8c08de3cb293b6607aaee8b13b3a671e267
- https://git.kernel.org/stable/c/4dc9f1517503c883d5ce25b7ab29d177d05edc6a
- https://git.kernel.org/stable/c/6a83d5e24a84e746425cd93539130e5f7381ef47
- https://git.kernel.org/stable/c/7cac59d08a73cb866ec51a483a6f3fe0f531947c
- https://git.kernel.org/stable/c/bb2040484f90f91b717060e1a66026cc4287bcf0