CVE Catalog

CVE-2021-47646

HighCVSS 7.8
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.28%

20th percentile - higher than 20% of all known CVEs

Summary

In the Linux kernel, a vulnerability related to the BFQ scheduler was fixed, which could lead to use-after-free (UAF). The commit regarding honoring already-setup queue merges was restored after being reverted, as the bug was fixed in another commit.

Risk Assessment

The vulnerability could lead to system crashes or potential privilege escalation, threatening system stability and security.

Recommendation

Update the Linux kernel to a version containing the fix.

Other vulnerabilities in Linux kernel

See all
Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: Revert "Revert "block, bfq: honor already-setup queue merges"" A crash [1] happened to be triggered in conjunction with commit 2d52c58b9c9b ("block, bfq: honor already-setup queue merges"). The latter was then reverted by commit ebc69e897e17 ("Revert "block, bfq: honor already-setup queue merges""). Yet, the reverted commit was not the one introducing the bug. In fact, it actually triggered a UAF introduced by a different commit, and now fixed by commit d29bd41428cf ("block, bfq: reset last_bfqq_created on group change"). So, there is no point in keeping commit 2d52c58b9c9b ("block, bfq: honor already-setup queue merges") out. This commit restores it. [1] https://bugzilla.kernel.org/show_bug.cgi?id=214503

Vulnerability data from NVD (NIST) · CISA KEV · EPSS