SB2026091915 - Deadlock in Linux kernel mailbox driver
Published: September 19, 2026
Security Bulletin ID
SB2026091915
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) Deadlock (CVE-ID: CVE-2026-90193)
CWE-ID: CWE-833 - Deadlock
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 improper locking in qcom_cpucp_mbox_irq_fn() when handling mailbox interrupts. A local user can trigger mailbox interrupt handling to cause a denial of service.
The issue occurs on systems using PREEMPT_RT, where the channel lock is converted to an rtmutex-based lock.
Remediation
Install update from vendor's website.