CVE-2026-99054: Linux kernel · tipc: destroy topsrv workqueues before closing connections
Source GCVE Database
Not known to be exploited · CVSS 7.8 High · fixed in fb717c536af2aafeca520ff11d1e0f25f7ab8fa9 : patch Linux kernel soon.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 4% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in fb717c536af2aafeca520ff11d1e0f25f7ab8fa9, da9c16568bc79140a54c1f5fcf07a0305df47b37, 7f796bb3b440d7f1b14c0e3b520462eb34f553af +2
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 23 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in– |
Description
In the Linux kernel, the following vulnerability has been resolved: tipc: destroy topsrv workqueues before closing connections tipc_topsrv_stop() closed subscriber connections while the topology server's send and receive workqueues were still running. Socket callbacks and subscription events could then queue more work, and in-flight send/recv work could drop the last connection reference during the conn_idr walk. That race produced several teardown failures: refcount_t addition on 0 from conn_get() on a connection whose release was blocked on idr_lock, a subsequent use-after-free in tipc_conn_close(), queue_work() on an already destroyed workqueue from the listener data-ready callback, and an RCU stall in tipc_topsrv_exit_net() while the walk spun under idr_lock. Clear srv->listener under idr_lock so it acts as a shutdown flag, skip queue_work() once it is NULL, destroy the workqueues to flush in-flight work, and only then close the remaining connections. Refuse tipc_conn_lookup() after that flag is cleared, and drop idr_lock when the teardown walk finds no connection, so an in-flight subscription event cannot pin idr_in_use while the walk holds the lock. v3 supersedes the narrower in-thread diff Tung Quang Nguyen posted on 2026-09-23. It keeps his teardown order and adds the lookup refusal and the empty-idr unlock.
References
- nvd.nist.gov/vuln/detail/CVE-2026-99054 (opens in a new tab)
- git.kernel.org/stable/c/0af8780bdfdfc91fb9127bddb9c48fab67dc9d9e (opens in a new tab)
- git.kernel.org/stable/c/3acdd44385bc7e2e57605e073691ce69cc5a960d (opens in a new tab)
- git.kernel.org/stable/c/7f796bb3b440d7f1b14c0e3b520462eb34f553af (opens in a new tab)
- git.kernel.org/stable/c/da9c16568bc79140a54c1f5fcf07a0305df47b37 (opens in a new tab)
- git.kernel.org/stable/c/fb717c536af2aafeca520ff11d1e0f25f7ab8fa9 (opens in a new tab)