CVE-2021-47281

Updated: 2025-01-14 17:51:30.28461

Description:

In the Linux kernel, the following vulnerability has been resolved: ALSA: seq: Fix race of snd_seq_timer_open() The timer instance per queue is exclusive, and snd_seq_timer_open() should have managed the concurrent accesses. It looks as if it's checking the already existing timer instance at the beginning, but it's not right, because there is no protection, hence any later concurrent call of snd_seq_timer_open() may override the timer instance easily. This may result in UAF, as the leftover timer instance can keep running while the queue itself gets closed, as spotted by syzkaller recently. For avoiding the race, add a proper check at the assignment of tmr->timeri again, and return -EBUSY if it's been already registered.


Links NIST CIRCL RHEL Ubuntu

Severity

Severity Score
CVSS Version 2.x 0
CVSS Version 3.x HIGH 7

Status

OS name Project name Version Score Severity Status Errata Last updated

Statement

CentOS 6 ELS kernel 2.6.32 7.0 HIGH In Rollout CLSA-2025:1739292069 2025-02-12 06:35:48
CloudLinux 6 ELS kernel 2.6.32 7.0 HIGH Needs Triage 2025-01-14 13:35:46
Oracle Linux 6 ELS kernel 2.6.32 7.0 HIGH Released CLSA-2025:1739352814 2025-02-13 01:22:44
Ubuntu 16.04 ELS linux-hwe 4.15.0 7.0 HIGH Released CLSA-2025:1738696174 2025-02-05 02:19:30
Ubuntu 16.04 ELS linux 4.4.0 7.0 HIGH In Testing 2025-01-21 00:20:47
Ubuntu 18.04 ELS linux 4.15.0 7.0 HIGH Released CLSA-2025:1738852812 2025-02-07 06:32:27