CVE-2026-80698 dmaengine: idxd: fix double free of wq, engine, and group structs
A double free vulnerability in the Linux kernel idxd driver allows local attackers to cause denial of service or potentially escalate privileges.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-80698?
CVE-2026-80698 is an use after free vulnerability in Linux, published on 28 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
dmaengine: idxd: fix double free of wq, engine, and group structs
The release callbacks for wq, engine, and group devices (idxd_conf_wq_release, idxd_conf_engine_release, idxd_conf_group_release) each call kfree() on the enclosing struct. The setup error paths and cleanup functions also call kfree() explicitly after put_device(), producing a double free whenever put_device() drops the reference count to zero and fires the release.
In the setup functions, device_initialize() is called before device_add(), so the reference count is exactly 1 at the error sites. put_device() unconditionally fires the release, which frees the struct; the subsequent explicit kfree() then operates on freed memory.
For idxd_setup_wqs(), the wq release callback also owns opcap_bmap and wqcfg. The error unwind additionally freed those fields explicitly before calling put_device(), causing further double frees on both.
Remove the redundant explicit kfree() calls from all setup error paths and cleanup functions for wq, engine, and group structs, delegating sole ownership of those allocations to the release callbacks.
Which versions are affected by CVE-2026-80698?
How do I fix CVE-2026-80698?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-80698 being exploited?
There is no known exploitation of CVE-2026-80698 in the wild and no public exploit code.
Sources
Also known as AZL-98153, BELL-CVE-2026-80698, DEBIAN-CVE-2026-80698, GHSA-5mr4-5v55-qp75, UBUNTU-CVE-2026-80698.