CVE-2026-99256
dm cache: fix issue with background work locking
- Published
- Updated
- Reserved
- Assigned by
- Linux
Description
In the Linux kernel, the following vulnerability has been resolved: dm cache: fix issue with background work locking dm cache used a rw_semaphore for background_work_lock. Write locks on rw_semaphores have strict owner semantics, but there was no guarantee that the process that locked background_work_lock was the same process that unlocked it. This can be easily seen using a kernel compiled with CONFIG_DEBUG_RWSEMS. Given a dm cache device <cache>, run: 'dmsetup suspend <cache> && dmsetup resume <cache>'. This will trigger a kernel warning: DEBUG_RWSEMS_WARN_ON((rwsem_owner(sem) != current) && !rwsem_test_oflags(sem, RWSEM_NONSPINNABLE)) triggered by cache_resume(). To fix this, switch from a rw_semaphore to a spinlock and a wait queue. dm cache already has a wait queue and associated counter, migration_wait and nr_allocated_migrations, that was getting woken up when background work was getting completed, but wasn't actually used by anything. This is replaced by the background_work queue and counter.
Timeline
ID reserved
By Linux
- 39 days later
· 39 days later
Published
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
No CVSS score yet: neither the CNA, CISA nor NVD has scored this CVE. NVD status: Received.
- EPSS (exploitation in 30 days)
- 0.20% · top 90% of all CVEs (7 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Not scored.
Affected products
- affected b29d4986d0da1a27cd35917cdb433672f5c95d7f – < 0c7a8cad7c96012a9157a189649e569d0390f384
- affected b29d4986d0da1a27cd35917cdb433672f5c95d7f – < f5db935d257023c3ef410bd39163b949b0e5a55d
- affected b29d4986d0da1a27cd35917cdb433672f5c95d7f – < 6290507ecc0dd6dd40759729cbbbd49b1d2a63c4
- affected b29d4986d0da1a27cd35917cdb433672f5c95d7f – < 8433fd005c25fd127021f67c9144a879fb585572
- affected b29d4986d0da1a27cd35917cdb433672f5c95d7f – < 2f2cfa16dd0f4179bb988139dd37d00a42324f6c
- affected b29d4986d0da1a27cd35917cdb433672f5c95d7f – < 73df2ff409f3db95029982fe3656329568e3715d
- affected b29d4986d0da1a27cd35917cdb433672f5c95d7f – < 104f09e02038b0fc6bbb718b3976af029e15c1d0
- affected b29d4986d0da1a27cd35917cdb433672f5c95d7f – < bc9781c0247de107876f32929f1637db93a42b34
- affected 4.12
- unaffected < 4.12
- unaffected 5.10.273 – ≤ 5.10.*
- unaffected 5.15.224 – ≤ 5.15.*
- unaffected 6.1.191 – ≤ 6.1.*
- unaffected 6.6.161 – ≤ 6.6.*
- unaffected 6.12.115 – ≤ 6.12.*
- unaffected 6.18.59 – ≤ 6.18.*
- unaffected 7.2.13 – ≤ 7.2.*
- unaffected 7.3 – ≤ *
References (8)
- https://git.kernel.org/stable/c/0c7a8cad7c96012a9157a189649e569d0390f384 (opens in a new tab)
- https://git.kernel.org/stable/c/f5db935d257023c3ef410bd39163b949b0e5a55d (opens in a new tab)
- https://git.kernel.org/stable/c/6290507ecc0dd6dd40759729cbbbd49b1d2a63c4 (opens in a new tab)
- https://git.kernel.org/stable/c/8433fd005c25fd127021f67c9144a879fb585572 (opens in a new tab)
- https://git.kernel.org/stable/c/2f2cfa16dd0f4179bb988139dd37d00a42324f6c (opens in a new tab)
- https://git.kernel.org/stable/c/73df2ff409f3db95029982fe3656329568e3715d (opens in a new tab)
- https://git.kernel.org/stable/c/104f09e02038b0fc6bbb718b3976af029e15c1d0 (opens in a new tab)
- https://git.kernel.org/stable/c/bc9781c0247de107876f32929f1637db93a42b34 (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-2026-99256)Record last updated .