CVE-2021-47281
Last modified
CVE-2021-47281 is a high-severity vulnerability rated 7/10 on the CVSS scale. 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. EPSS estimates a 0.23% chance of exploitation in the next 30 days.
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.
Metrics
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness Enumeration
Affected Software
| Vendor | Product | Versions | Update |
|---|---|---|---|
| Linux | Linux Kernel | < 5.10.44 | — |
| Linux | Linux Kernel | >= 5.11, < 5.12.11 | — |
| Linux | Linux Kernel | 5.13 | Rc1 |
References
Timeline
- Published
- Last Modified
- Status
- Modified
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- CVE-2021-47285Rejected reason: This CVE ID has been rejected or withdrawn …
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