Vulnerability · CVE-2026-99103
workqueue: Fix unbound pool lifetime for pending pwqs
Published Oct 28, 2026 · catalog updated Oct 29, 2026 · Linux Linux
Last checked Nov 6, 2026. A connected source was read within the last 7 days.
Check if you run it
No confirmed exploitation is on record for CVE-2026-99103. EPSS is 0.17%. Act only if a listed version of Linux Linux is installed.
Gaps on this record
- No vendor fix or required action is stored. Compare the linked advisory before you change production.
Same product and reporting
- CVE-2026-99260 · Medium
- CVE-2026-99259 · Medium
- CVE-2026-99258 · High
- CVE-2026-99257 · Medium
- CVE-2026-99255 · Medium
- Severity
- Unknown—
- Known exploitation
- Not in CISA/VulnCheck KEV
- EPSS
- 0.17%
- Remediation
- Advisory link
- Affected products
- Linux Kernel · vendor Linux Linux
In the Linux kernel, the following vulnerability has been resolved: workqueue: Fix unbound pool lifetime for pending pwqs KASAN reports a use-after-free of an unbound worker_pool in node_activate_pending_pwq(): BUG: KASAN: slab-use-after-free in _raw_spin_trylock+0x6d/0x120 Read of size 4 at addr ffff8880089ce000 by task kworker/u22:0/318 CPU: 1 UID: 0 PID: 318 Comm: kworker/u22:0 Not tainted 7.2.0 #1 PREEMPT(lazy) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 Workqueue: 0x0 (flush-8:0) Call Trace: dump_stack_lvl+0x53/0x70 print_report+0xce/0x610 kasan_report+0xce/0x100 _raw_spin_trylock+0x6d/0x120 pwq_dec_nr_in_flight+0x4b4/0xcb0 process_one_work+0x921/0x11a0 worker_thread+0x4d0/0xd20 kthread+0x2de/0x3c0 ret_from_fork+0x3aa/0x620 ret_from_fork_asm+0x1a/0x30 Allocated by task 311: alloc_pwq+0x439/0xca0 apply_wqattrs_prepare+0x75e/0xd10 apply_workqueue_attrs_locked+0x44/0xa0 wq_nice_store+0x350/0x450 Freed by task 0: kfree+0x127/0x3b0 rcu_core+0x523/0x1780 handle_softirqs+0x1b3/0x610 Last potentially related work creation: put_unbound_pool+0x3f3/0x7d0 pwq_release_workfn+0x494/0x8e0 kthread_worker_fn+0x1ff/0x790 Canceling the last inactive work skips pwq_dec_nr_active(), so an empty pwq can remain on pending_pwqs when its refcnt reaches zero. pwq_release_workfn() currently puts the pool before removing that pwq. If this drops the last pool reference, the pool can be RCU-freed while the pwq remains reachable, and node_activate_pending_pwq() may trylock the freed pool->lock. Remove the pwq from pending_pwqs before putting the pool.
Are you affected?
Enter the version you run. The result uses only the ranges stored on this record.
The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.
- Linux Kernel0 → 6.6.25; 6.7.0 → 6.8.4; 6.9.0 → 6.18.59
- vendor Linux Linuxversion unspecified
How to fix CVE-2026-99103
Upgrade
CVE-2026-99103 lists a fix boundary at 6.6.25. Compare the installed build with that boundary before you change production.
Version check
Fixed in 6.6.25; 6.7.0
Advisory
Open the bsi record and follow its fix.
Official advisories
What to do
Three questions, each answered from this record only. Confirm the vendor advisory before you patch.
Should you patch?
No confirmed exploitation is on record for CVE-2026-99103. EPSS is 0.17%. Act only if a listed version of Linux Linux is installed.
Which versions are affected?
Compare what you have installed with Kernel 0 → 6.6.25; 6.7.0 → 6.8.4; 6.9.0 → 6.18.59. Compare the installed version with the linked vendor advisory before you change production.
What should an analyst verify?
No weakness class is stored. EPSS 0.17%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.
Code
The project this record applies to. Exploit listings stay in References.
Timeline
Detection, updates, and resolution for this record.
Oct 28, 2026 · OpenSSF OSV / OSV Scanner
Detected
In the Linux kernel, the following vulnerability has been resolved: workqueue: Fix unbound pool lifetime for pending pwqs KASAN reports a use-after-free of an unbound worker_pool in node_activate_pending_pwq(): BUG: KASAN: slab-use-after-free in _raw_spin_trylock+0x6d/0x120 Read of size 4 at addr ffff8880089ce000 by task kworker/u22:0/318 CPU: 1 UID: 0 PID: 318 Comm: kworker/u22:0 Not tainted 7.2.
Oct 29, 2026 · OpenSSF OSV / OSV Scanner
Fix available
Kernel fixed in 6.6.25; Kernel fixed in 6.8.4; Kernel fixed in 6.18.59
Oct 29, 2026 · OpenSSF OSV / OSV Scanner
Fix available
Kernel fixed in 6.6.25; 6.7.0
Oct 29, 2026 · OpenSSF OSV / OSV Scanner
Updated
In the Linux kernel, the following vulnerability has been resolved: workqueue: Fix unbound pool lifetime for pending pwqs KASAN reports a use-after-free of an unbound worker_pool in node_activate_pending_pwq(): BUG: KASAN: slab-use-after-free in _raw_spin_trylock+0x6d/0x120 Read of size 4 at addr ffff8880089ce000 by task kworker/u22:0/318 CPU: 1 UID: 0 PID: 318 Comm: kworker/u22:0 Not tainted 7.2.
Sources
- BSI CERT-BundGovernment advisoryCVE-2026-99103
Linux Kernel: Mehrere Schwachstellen ermöglichen nicht spezifizierten Angriff
wid.cert-bund.de - CVE.orgVulnerability recordCVE-2026-99103
In the Linux kernel, the following vulnerability has been resolved: workqueue: Fix unbound pool lifetime for pending pwqs KASAN reports a use-after-free of an unbound worker_pool in node_activate_pending_pwq(): BUG: KASAN: slab-use-after-free in _raw_spin_trylock+0x6d/0x120 Read
cve.org - FIRST EPSSExploitation probabilityCVE-2026-99103
30-day exploitation probability 0.17%
first.org - OpenSSF OSV / OSV ScannerPackage advisoryCVE-2026-99103
workqueue: Fix unbound pool lifetime for pending pwqs
osv.dev
References
Freshness
Last verified in this catalog Nov 6, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.
- FIRST EPSSOct 31, 2026
- BSI CERT-BundOct 30, 2026
- CVE.orgOct 29, 2026
- OpenSSF OSV / OSV ScannerOct 29, 2026