CVE-2021-47646

HIGH EPSS 16.0%
Published Feb 26, 20251y ago · Modified Jun 17, 20262w ago
7.8 CVSS 3.1
High
Find Similar
Published Feb 26, 2025 1y ago
Last Modified Jun 17, 2026 2w ago

Description

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

CVSS Details

Base Score
7.8
Exploitability
1.8
Impact
5.9
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack Vector Local
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope Unchanged
Confidentiality High
Integrity High
Availability High

Threat Intelligence

EPSS Exploit Probability
16.0% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Weaknesses 1

CWE-416 Use After Free Memory Safety

Affected Products 6

VendorProductVersionRange
linuxlinux_kernel* <4.19.238
linuxlinux_kernel*≥4.20  –  <5.4.189
linuxlinux_kernel*≥5.5  –  <5.10.110
linuxlinux_kernel*≥5.11  –  <5.15.33
linuxlinux_kernel*≥5.16  –  <5.16.19
linuxlinux_kernel*≥5.17  –  <5.17.2

References 7

  • git.kernel.org https://git.kernel.org/stable/c/15729ff8143f8135b03988a100a19e66d7cb7ecd
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/4083925bd6dc89216d156474a8076feec904e607
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/65d8a737452e88f251fe5d925371de6d606df613
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/931aff627469a75c77b9fd3823146d0575afffd6
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/abc2129e646af7b43025d90a071f83043f1ae76c
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/cc051f497eac9d8a0d816cd4bffa3415f2724871
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/f990f0985eda59d4f29fc83fcf300c92b1225d39
    Patch

Remediation

  • git.kernel.org https://git.kernel.org/stable/c/15729ff8143f8135b03988a100a19e66d7cb7ecd
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/4083925bd6dc89216d156474a8076feec904e607
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/65d8a737452e88f251fe5d925371de6d606df613
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/931aff627469a75c77b9fd3823146d0575afffd6
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/abc2129e646af7b43025d90a071f83043f1ae76c
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/cc051f497eac9d8a0d816cd4bffa3415f2724871
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/f990f0985eda59d4f29fc83fcf300c92b1225d39
    Patch