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

Source: https://junglewise.ai/threats/cve-2026-99230-in-the-linux-kernel-the-following-vulnerability-has-been-resolved  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-02. Updated: 2026-11-02  
License: CC BY 4.0 with a link back

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](https://junglewise.ai/threats/technologies/x-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

- [https://git.kernel.org/stable/c/2d5af21422060c088f6e4fb0f1e7dcf5bcdd6707](https://git.kernel.org/stable/c/2d5af21422060c088f6e4fb0f1e7dcf5bcdd6707)
- [https://git.kernel.org/stable/c/685b49483200384d7f49d338af476e26e6824637](https://git.kernel.org/stable/c/685b49483200384d7f49d338af476e26e6824637)

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