CVE-2021-47646
Revert "Revert "block, bfq: honor already-setup queue merges""
- Published
- Updated
- Reserved
- Assigned by
- Linux
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
Timeline
ID reserved
By Linux
Published
- 18 months later
· 18 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| LinuxCNA (assigner) | 3.1 | High7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| CISA-ADPADP (enrichment) | 3.1 | High7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| NVDNVD · Modified | 3.1 | High7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 0.28% · top 79% of all CVEs (7 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.8.
Weakness
Affected products
- affected 430a67f9d6169a7b3e328bceb2ef9542e4153c7c – < 65d8a737452e88f251fe5d925371de6d606df613
- affected 430a67f9d6169a7b3e328bceb2ef9542e4153c7c – < abc2129e646af7b43025d90a071f83043f1ae76c
- affected 430a67f9d6169a7b3e328bceb2ef9542e4153c7c – < 4083925bd6dc89216d156474a8076feec904e607
- affected 430a67f9d6169a7b3e328bceb2ef9542e4153c7c – < 15729ff8143f8135b03988a100a19e66d7cb7ecd
- affected 5.13
- unaffected < 5.13
- unaffected 5.15.33 – ≤ 5.15.*
- unaffected 5.16.19 – ≤ 5.16.*
- unaffected 5.17.2 – ≤ 5.17.*
- unaffected 5.18 – ≤ *
References (4)
- https://git.kernel.org/stable/c/65d8a737452e88f251fe5d925371de6d606df613 (opens in a new tab)
- https://git.kernel.org/stable/c/abc2129e646af7b43025d90a071f83043f1ae76c (opens in a new tab)
- https://git.kernel.org/stable/c/4083925bd6dc89216d156474a8076feec904e607 (opens in a new tab)
- https://git.kernel.org/stable/c/15729ff8143f8135b03988a100a19e66d7cb7ecd (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2021-47646)Record last updated .