# CVE-2026-23009: linux: In the Linux kernel, the following vulnerability has been resolved:  xhci: sideband: don't dereference freed ring whe...

CVE-2026-23009 is fixed in linux on 1 platform by DEBIAN-CVE-2026-23009 (version 6.18.8-1), released January 25, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-23009
- Priority: Routine
- CVSS: 5.5 (medium)
- EPSS: 0.0016
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jan 25, 2026

## Description

In the Linux kernel, the following vulnerability has been resolved:  xhci: sideband: don't dereference freed ring when removing sideband endpoint  xhci_sideband_remove_endpoint() incorrecly assumes that the endpoint is running and has a valid transfer ring.  Lianqin reported a crash during suspend/wake-up stress testing, and found the cause to be dereferencing a non-existing transfer ring 'ep->ring' during xhci_sideband_remove_endpoint().  The endpoint and its ring may be in unknown state if this function is called after xHCI was reinitialized in resume (lost power), or if device is being re-enumerated, disconnected or endpoint already dropped.  Fix this by both removing unnecessary ring access, and by checking ep->ring exists before dereferencing it. Also make sure endpoint is running before attempting to stop it.  Remove the xhci_initialize_ring_info() call during sideband endpoint removal as is it only initializes ring structure enqueue, dequeue and cycle state values to their starting values without changing actual hardware enqueue, dequeue and cycle state. Leaving them out of sync is worse than leaving it as it is. The endpoint will get freed in after this in most usecases.  If the (audio) class driver want's to reuse the endpoint after offload then it is up to the class driver to ensure endpoint is properly set up.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 14 | 6.18.8-1 | [DEBIAN-CVE-2026-23009](https://patchblox.com/security/data/fix/linux/debian-cve-2026-23009.md) | Jan 25, 2026 |

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Data as of 2026-11-08T06:59:42Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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