CVE-2026-92508: RDMA/core: Fix potential use after free in ib_free_cq()

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: 2026-09-17 · updated 2026-10-19

Description

In the Linux kernel, the following vulnerability has been resolved: RDMA/core: Fix potential use after free in ib_free_cq() When accessing a CQ via the netlink path the only synchronization mechanism for the said CQ is rdma_restrack_get(). Currently, rdma_restrack_del() is invoked at the end of ib_free_cq(), which is too late, since by that point vendor-specific resources associated with the CQ might already be freed. This can leave a short window where the CQ remains accessible through restrack, leading to a potential use-after-free. Fix this by moving the rdma_restrack_del() call to be before the freeing of the vendor-specific resources ensuring that the CQ is removed from restrack before its internal resources are released. This guarantees that no new users hold references to a CQ that is in the process of destruction.

Affected products

Linux kernel: from 5.8.17 before 5.9; from 5.9.2 before 5.10; 5.10 — fixed in 5.10, 5.9, 7.3

How to fix

Upgrade to a fixed version: Linux kernel 5.10, 5.9, 7.3. Check the vendor advisory for mitigations.

References

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