CVE-2026-99230: Linux kernel io_uring memory corruption via list poisoning

CVE-2026-99230 · Severity: info · Published 2026-11-02

The Linux kernel's io_uring subsystem contains a memory corruption bug where improperly cleaned-up data structures can cause a general protection fault. When certain asynchronous I/O operations are recycled through a request cache without full reinitialization, stale poison values from previous operations can trigger crashes in subsequent operations, leading to kernel panics and system instability.

Technologies: Linux kernel.

Quick answers

Is CVE-2026-99230 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-99230 being exploited in the wild.
How severe is CVE-2026-99230?
Informational severity, published 2 November 2026.
Which products and versions are affected?
Linux kernel affected versions not explicitly stated in advisory.
Is there a fix for CVE-2026-99230?
Yes: fixed in Addressed by changing hlist_del() to hlist_del_init() in io_uring/uring_cmd.c (commit 4c83e39f4d1944d7146fd06094f2c8053238d55c upstream). Until then: Update to a Linux kernel version that includes the fix to use hlist_del_init() instead of hlist_del() in the io_uring_cmd_del_cancelable() function. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-99230 attacked?
It is attacked with local access, in an operating system.
Am I affected by CVE-2026-99230?
Check whether you run Linux kernel at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • Fixed in: Addressed by changing hlist_del() to hlist_del_init() in io_uring/uring_cmd.c (commit 4c83e39f4d1944d7146fd06094f2c8053238d55c upstream)

Update to a Linux kernel version that includes the fix to use hlist_del_init() instead of hlist_del() in the io_uring_cmd_del_cancelable() function.

Technical details

The vulnerability exists in io_uring_cmd_del_cancelable() which uses hlist_del() instead of hlist_del_init() when removing a cancelable uring_cmd from the cancelable_uring_cmd list. This leaves LIST_POISON values in the hash_node field. When requests are recycled through the cache, subsequent operations (such as vectored futex waits) that reuse the hash_node without reinitializing it will dereference the poison value, causing a general protection fault and kernel panic.

Affected products

  • Linux kernel affected versions not explicitly stated in advisory

Timeline

  • 2026-10-15: disclosed
  • 2026-10-30: patched

References

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