# CVE-2026-99270: Linux kernel TCP use-after-free in reqsk_timer_handler

Source: https://junglewise.ai/threats/cve-2026-99270-in-the-linux-kernel-the-following-vulnerability-has-been-resolved  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-03. Updated: 2026-11-03  
License: CC BY 4.0 with a link back

CVE-2026-99270 · Severity: info · Published 2026-11-03

A vulnerability in the Linux kernel's TCP connection handling can cause a use-after-free error when socket migration fails. An attacker with network access could trigger this condition to cause a kernel crash or potentially execute code with kernel privileges.

Technologies: [Linux Kernel](https://junglewise.ai/threats/technologies/kernel). Vendors: [Linux](https://junglewise.ai/threats/vendors/linux).

## Quick answers

**Is CVE-2026-99270 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-99270 being exploited in the wild.

**How severe is CVE-2026-99270?** Informational severity, published 3 November 2026.

**Which products and versions are affected?** Linux Linux kernel.

**Is there a fix for CVE-2026-99270?** A patch was published on 2026-05-08. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-99270 attacked?** It is attacked over the network, in an operating system.

**Am I affected by CVE-2026-99270?** Check whether you run Linux Kernel. 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.

## Technical details

A use-after-free (UAF) in reqsk_timer_handler() occurs when TCP socket migration fails at inet_ehash_insert() and the code jumps to the no_ownership label, freeing a request socket immediately without stopping its associated timer. The timer may then fire and reference freed memory. The fix ensures the timer is properly stopped before freeing by passing false to __inet_csk_reqsk_queue_drop().

## Affected products

- Linux Linux kernel

## Timeline

- 2026-11-03: disclosed
- 2026-05-08: patched

## References

- [https://git.kernel.org/stable/c/97c8a3c1f73d828de43a5a88e8a9a143efb2b661](https://git.kernel.org/stable/c/97c8a3c1f73d828de43a5a88e8a9a143efb2b661)

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