CVE-2026-80555 s390/vfio_ccw: Free all memory if cp_init() fails
A memory leak in the s390 vfio_ccw driver allows attackers to cause denial of service by triggering initialization failures.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-80555?
CVE-2026-80555 is a high-severity memory corruption vulnerability in Linux, published on 26 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:
s390/vfio_ccw: Free all memory if cp_init() fails
The routine cp_free() is called to unpin/free any memory once an I/O is completed successfully, or if cp_prefetch() fails. But if cp_init() fails, and cp->initialized is not enabled, the same routine cannot be used to free all the memory.
An attempt to address this exists in ccwchain_handle_ccw(), where a single call to ccwchain_free() is made for the currently-processed CCW segment. But this will leak other segments (created as a result of a Transfer in Channel) that had been allocated as part of the same channel program.
Address this by performing the cleanup outside of the recursive ccwchain_handle_ccw()/ccwchain_loop_tic() logic.
Which versions are affected by CVE-2026-80555?
How do I fix CVE-2026-80555?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-80555 being exploited?
There is no known exploitation of CVE-2026-80555 in the wild and no public exploit code.
Sources
Also known as AZL-97758, BELL-CVE-2026-80555, DEBIAN-CVE-2026-80555, GHSA-w6fw-g579-ffcw, UBUNTU-CVE-2026-80555.