CVE-2026-63797: rpmsg: char: Fix use-after-free on probe error path

Severity: high (CVSS 8.4 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: 2026-07-19 · updated 2026-08-17
Weakness: CWE-416

Description

In the Linux kernel, the following vulnerability has been resolved: rpmsg: char: Fix use-after-free on probe error path rpmsg_chrdev_probe() stores the newly allocated eptdev in the default endpoint's priv pointer before calling rpmsg_chrdev_eptdev_add(). If rpmsg_chrdev_eptdev_add() then fails, its error path frees eptdev while the default endpoint may still dispatch callbacks with the stale priv pointer. Avoid publishing eptdev through the default endpoint until rpmsg_chrdev_eptdev_add() succeeds. Messages received before the priv pointer is published should be ignored by rpmsg_ept_cb(). Flow-control updates can hit rpmsg_ept_flow_cb() in the same window, so make both callbacks return success when priv is NULL.

Affected products

Linux kernel: from 5.18 before 6.1.178; from 6.2 before 6.6.144; from 6.7 before 6.12.95; from 6.13 before 6.18.38; from 6.19 before 7.1.3 — fixed in 6.1.178, 6.12.95, 6.18.38, 6.6.144, 7.1.3

How to fix

Upgrade to a fixed version: Linux kernel 6.1.178, 6.12.95, 6.18.38, 6.6.144. Check the vendor advisory for mitigations.

References

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