CVE-2026-31532: can: raw: fix ro->uniq use-after-free in raw_rcv()

Severity: high (CVSS 7.8 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: 2026-04-23 · updated 2026-10-19
Weakness: CWE-416

Description

In the Linux kernel, the following vulnerability has been resolved: can: raw: fix ro->uniq use-after-free in raw_rcv() raw_release() unregisters raw CAN receive filters via can_rx_unregister(), but receiver deletion is deferred with call_rcu(). This leaves a window where raw_rcv() may still be running in an RCU read-side critical section after raw_release() frees ro->uniq, leading to a use-after-free of the percpu uniq storage. Move free_percpu(ro->uniq) out of raw_release() and into a raw-specific socket destructor. can_rx_unregister() takes an extra reference to the socket and only drops it from the RCU callback, so freeing uniq from sk_destruct ensures the percpu area is not released until the relevant callbacks have drained. [mkl: applied manually]

Affected products

Linux kernel: from 4.1 through 6.6.136; from 6.7 before 6.12.83; from 6.18 before 6.18.24; from 6.19 before 6.19.14; from 7.0 before 7.0.1 — fixed in 6.12.83, 6.18.24, 6.19.14, 7.0.1

How to fix

Upgrade to a fixed version: Linux kernel 6.12.83, 6.18.24, 6.19.14, 7.0.1. Check the vendor advisory for mitigations.

References

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