CVE-2026-63885: drm/gem: fix race between change_handle and handle_delete

Severity: high (CVSS 8.8 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: 2026-07-19 · updated 2026-10-26
Weakness: CWE-362

Description

In the Linux kernel, the following vulnerability has been resolved: drm/gem: fix race between change_handle and handle_delete drm_gem_change_handle_ioctl leaves the old handle live in the IDR during the window between spin_unlock(table_lock) and the final spin_lock(table_lock). A concurrent drm_gem_handle_delete on the old handle succeeds in this window, decrements handle_count to 0, and frees the GEM object while the new handle's IDR entry still references it. NULL the old handle's IDR entry before dropping table_lock so that any concurrent GEM_CLOSE on the old handle sees NULL and returns -EINVAL. Restore the old entry on the prime-bookkeeping error path.

Affected products

Linux kernel: from 6.18.32 before 6.18.35; from 7.0.9 before 7.0.12; 7.1-rc3, 7.1-rc4, 7.1-rc5 — fixed in 6.18.35, 7.0.12
Linux kernel: from 6.18.32 before 6.18.35; from 7.0.9 before 7.0.12 — fixed in 6.18.35, 7.0.12

How to fix

Upgrade to a fixed version: Linux kernel 6.18.35, 7.0.12; Linux kernel 6.18.35, 7.0.12. Check the vendor advisory for mitigations.

References

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