mm: blk-cgroup: fix use-after-free in cgwb_release_workfn()
In the Linux kernel, the following vulnerability has been resolved: mm: blk-cgroup: fix use-after-free in cgwb_release_workfn() cgwb_release_workfn() calls css_put(wb->blkcg_css) and then later accesses wb->blkcg_css again via blkcg_unpin_online(). If css_put() drops the last reference, the blkcg can be freed asynchronously (css_free_rwork_fn -> blkcg_css_free -> kfree) before blkcg_unpin_online() dereferences the pointer to access blkcg->online_pin, resulting in a use-after-free: BUG: KASAN: slab-use-after-free in blkcg_unpin_online (./include/linux/instrumented.h:112 ./include/linux/atomic/atomic-instrumented.h:400 ./include/linux/refcount.h:389 ./include/linux/refcount.h:432 ./include/linux/refcount.h:450 block/blk-cgroup.c:1367) Write of size 4 at addr ff11000117aa6160 by task kworker/71:1/531 Workqueue: cgwb_release cgwb_release_workfn Call Trace: blkcg_unpin_online (./include/linux/instrumented.h:112 ./include/linux/atomic/atomic-instrumented.h:400 ./include/linux/refcount.h:389 ./include/linux/refcount.h:432 ./include/linux/refcount.h:450 block/blk-cgroup.c:1367) cgwb_release_workfn (mm/backing-dev.c:629) process_scheduled_works (kernel/workqueue.c:3278 kernel/workqueue.c:3385) Freed by task 1016: kfree (./include/linux/kasan.h:235 mm/slub.c:2689 mm/slub.c:6246 mm/slub.c:6561) css_free_rwork_fn (kernel/cgroup/cgroup.c:5542) process_scheduled_works (kernel/workqueue.c:3302 kernel/workqueue.c:3385) ** Stack based on commit 66672af7a095 ("Add linux-next specific files for
CVE-2026-31586
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-31586
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "59b57717fff8b562825d9d25e0180ad7e8048ca9",
"lessThan": "23acef4156c260e8598397a1a2e8b3a23e919893",
"versionType": "git"
},
{
"status": "affected",
"version": "59b57717fff8b562825d9d25e0180ad7e8048ca9",
"lessThan": "1bd36e93b542d9dd020190c6607c6a3663405195",
"versionType": "git"
},
{
"status": "affected",
"version": "59b57717fff8b562825d9d25e0180ad7e8048ca9",
"lessThan": "740ba1ebb223f137ff088ab74d533a13f9167bd8",
"versionType": "git"
},
{
"status": "affected",
"version": "59b57717fff8b562825d9d25e0180ad7e8048ca9",
"lessThan": "115a5266749dcde7fe4127e8623d19c752088f69",
"versionType": "git"
},
{
"status": "affected",
"version": "59b57717fff8b562825d9d25e0180ad7e8048ca9",
"lessThan": "dfc8292a1d6782c76b626315605e0585a5a18447",
"versionType": "git"
},
{
"status": "affected",
"version": "59b57717fff8b562825d9d25e0180ad7e8048ca9",
"lessThan": "ea3af09eb87d8f8708c66747fcf1a2762902e839",
"versionType": "git"
},
{
"status": "affected",
"version": "59b57717fff8b562825d9d25e0180ad7e8048ca9",
"lessThan": "50879a3c1faf06e661090015d59e2127255cff27",
"versionType": "git"
},
{
"status": "affected",
"version": "59b57717fff8b562825d9d25e0180ad7e8048ca9",
"lessThan": "67cb119d32f35e32acd0393bbeb318b2bb1fdafe",
"versionType": "git"
},
{
"status": "affected",
"version": "59b57717fff8b562825d9d25e0180ad7e8048ca9",
"lessThan": "8f5857be99f1ed1fa80991c72449541f634626ee",
"versionType": "git"
}
],
"programFiles": [
"mm/backing-dev.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "4.19"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "4.19",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.10.258",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"status": "unaffected",
"version": "5.15.209",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.175",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.136",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.83",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.24",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "6.19.14",
"versionType": "semver",
"lessThanOrEqual": "6.19.*"
},
{
"status": "unaffected",
"version": "7.0.1",
"versionType": "semver",
"lessThanOrEqual": "7.0.*"
},
{
"status": "unaffected",
"version": "7.1",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"mm/backing-dev.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-31586
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #39924 · Revision 1
- Added to Heist Feed
- Publisher date