CVE-2025-37813: usb: xhci: Fix invalid pointer dereference in Etron workaround

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-05-08 · updated 2026-10-15
Weakness: CWE-476

Description

In the Linux kernel, the following vulnerability has been resolved: usb: xhci: Fix invalid pointer dereference in Etron workaround This check is performed before prepare_transfer() and prepare_ring(), so enqueue can already point at the final link TRB of a segment. And indeed it will, some 0.4% of times this code is called. Then enqueue + 1 is an invalid pointer. It will crash the kernel right away or load some junk which may look like a link TRB and cause the real link TRB to be replaced with a NOOP. This wouldn't end well. Use a functionally equivalent test which doesn't dereference the pointer and always gives correct result. Something has crashed my machine twice in recent days while playing with an Etron HC, and a control transfer stress test ran for confirmation has just crashed it again. The same test passes with this patch applied.

Affected products

Linux kernel: from 6.6.66 before 6.6.89; from 6.11.11 before 6.12; from 6.12.2 before 6.12.26; from 6.13 before 6.14.5; 6.15-rc1, 6.15-rc2, 6.15-rc3 — fixed in 6.12, 6.12.26, 6.14.5, 6.6.89

How to fix

Upgrade to a fixed version: Linux kernel 6.12, 6.12.26, 6.14.5, 6.6.89. Check the vendor advisory for mitigations.

References

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