CVE-2026-99218: Linux kernel · coredump: hold RCU while releasing parked threads
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.0 High.
Data as of 5 Nov 2026, 12:35 UTC
Thin evidence
One scorer or none| CNA (Linux) | CVSS 3.1 | 7.0 |
|---|
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 2 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 5 Nov 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.10linuxpkg:deb/ubuntu/linux?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-oraclepkg:deb/ubuntu/linux-oracle?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
Description
In the Linux kernel, the following vulnerability has been resolved: coredump: hold RCU while releasing parked threads coredump_finish() releases the parked threads by clearing ->task in their core_thread entry and calling wake_up_process() on each of them. It does that without holding a reference on the task and without being inside rcu. But calling wake_up_process(task) without rcu here isn't safe. A parked thread doesn't need that wakeup to leave. A spurious wakeup or a preemption after the store is enough for the task to go away. So if the coredump client is preempted between the store and wake_up_process() the thread can exit and be freed in the meantime and try_to_wake_up() takes pi_lock in freed memory. Hold rcu across the loop.
References
- ubuntu.com/security/CVE-2026-99218 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-99218 (opens in a new tab)
- git.kernel.org/stable/c/16e94ed90b1b02398e044d41fd1db34828daa08e (opens in a new tab)
- git.kernel.org/stable/c/fd0fbe84312fda2fc187428c92c50b7d03a9d24c (opens in a new tab)
- git.kernel.org/stable/c/71146c437bae59e5280f657965dc6d006ee3989b (opens in a new tab)
- git.kernel.org/stable/c/a0f09ff4c6b93312e565cfe75d76c3a551a3ec4c (opens in a new tab)
- git.kernel.org/stable/c/0fce73efee40c65ce26641c5d93942462f9e8307 (opens in a new tab)
- git.kernel.org/stable/c/b0eca0edddf4c1dbaf6d1f6a8636b4235f5bc573 (opens in a new tab)