CVE-2021-47281
ALSA seq Use After Free (UAF) Vulnerability
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.
INFO
Published Date :
May 21, 2024, 3:15 p.m.
Last Modified :
Dec. 24, 2024, 4:30 p.m.
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Remotely Exploitable :
No
Impact Score :
5.9
Exploitability Score :
1.0
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2021-47281.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2021-47281 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2021-47281 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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Initial Analysis by [email protected]
Dec. 24, 2024
Action Type Old Value New Value Added CVSS V3.1 NIST AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H Added CWE NIST CWE-416 Added CPE Configuration OR *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions up to (excluding) 5.10.44 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.11 up to (excluding) 5.12.11 *cpe:2.3:o:linux:linux_kernel:5.13:rc1:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:5.13:rc2:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:5.13:rc3:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:5.13:rc4:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:5.13:rc5:*:*:*:*:*:* Changed Reference Type https://git.kernel.org/stable/c/536a7646c00a0f14fee49e5e313109e5da2f6031 No Types Assigned https://git.kernel.org/stable/c/536a7646c00a0f14fee49e5e313109e5da2f6031 Patch Changed Reference Type https://git.kernel.org/stable/c/536a7646c00a0f14fee49e5e313109e5da2f6031 No Types Assigned https://git.kernel.org/stable/c/536a7646c00a0f14fee49e5e313109e5da2f6031 Patch Changed Reference Type https://git.kernel.org/stable/c/83e197a8414c0ba545e7e3916ce05f836f349273 No Types Assigned https://git.kernel.org/stable/c/83e197a8414c0ba545e7e3916ce05f836f349273 Patch Changed Reference Type https://git.kernel.org/stable/c/83e197a8414c0ba545e7e3916ce05f836f349273 No Types Assigned https://git.kernel.org/stable/c/83e197a8414c0ba545e7e3916ce05f836f349273 Patch Changed Reference Type https://git.kernel.org/stable/c/bd7d88b0874f82f7b29d1a53e574cedaf23166ba No Types Assigned https://git.kernel.org/stable/c/bd7d88b0874f82f7b29d1a53e574cedaf23166ba Patch Changed Reference Type https://git.kernel.org/stable/c/bd7d88b0874f82f7b29d1a53e574cedaf23166ba No Types Assigned https://git.kernel.org/stable/c/bd7d88b0874f82f7b29d1a53e574cedaf23166ba Patch -
CVE Modified by af854a3a-2127-422b-91ae-364da2661108
Nov. 21, 2024
Action Type Old Value New Value Added Reference https://git.kernel.org/stable/c/536a7646c00a0f14fee49e5e313109e5da2f6031 Added Reference https://git.kernel.org/stable/c/83e197a8414c0ba545e7e3916ce05f836f349273 Added Reference https://git.kernel.org/stable/c/bd7d88b0874f82f7b29d1a53e574cedaf23166ba -
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
May. 28, 2024
Action Type Old Value New Value -
CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
May. 21, 2024
Action Type Old Value New Value Added 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. Added Reference kernel.org https://git.kernel.org/stable/c/bd7d88b0874f82f7b29d1a53e574cedaf23166ba [No types assigned] Added Reference kernel.org https://git.kernel.org/stable/c/536a7646c00a0f14fee49e5e313109e5da2f6031 [No types assigned] Added Reference kernel.org https://git.kernel.org/stable/c/83e197a8414c0ba545e7e3916ce05f836f349273 [No types assigned]
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2021-47281 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2021-47281
weaknesses.