CVE-2026-46267: nfc: hci: shdlc: Stop timers and work before freeing context

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-06-03 · updated 2026-07-22
Weakness: CWE-416

Description

In the Linux kernel, the following vulnerability has been resolved: nfc: hci: shdlc: Stop timers and work before freeing context llc_shdlc_deinit() purges SHDLC skb queues and frees the llc_shdlc structure while its timers and state machine work may still be active. Timer callbacks can schedule sm_work, and sm_work accesses SHDLC state and the skb queues. If teardown happens in parallel with a queued/running work item, it can lead to UAF and other shutdown races. Stop all SHDLC timers and cancel sm_work synchronously before purging the queues and freeing the context. Found by Linux Verification Center (linuxtesting.org) with SVACE.

Affected products

Linux kernel: from 3.7 before 5.15.202; from 5.16 before 6.1.165; from 6.2 before 6.6.128; from 6.7 before 6.12.75; from 6.13 before 6.18.14; from 6.19 before 6.19.4 — fixed in 5.15.202, 6.1.165, 6.12.75, 6.18.14, 6.19.4, 6.6.128

How to fix

Upgrade to a fixed version: Linux kernel 5.15.202, 6.1.165, 6.12.75, 6.18.14. Check the vendor advisory for mitigations.

References

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