CVE-2026-89552 params: fix charp corruption on allocation failure
A local attacker with high privileges can trigger a kernel NULL pointer dereference and system crash by causing a memory allocation failure during parameter updates.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-89552?
CVE-2026-89552 is a vulnerability in Linux, published on 11 Sep 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:
params: fix charp corruption on allocation failure
param_set_charp() stores charp parameters in allocated memory after slab is available, and releases the previous value when the parameter is updated.
The previous value is released before the replacement allocation succeeds. If kmalloc_parameter() fails, the setter returns -ENOMEM with the parameter left as NULL.
Failing zswap's compressor update before zswap is initialized can later trigger:
BUG: kernel NULL pointer dereference, address: 0000000000000000 RIP: 0010:strcmp+0x10/0x30 Call Trace: zswap_setup+0x3b1/0x490 zswap_enabled_param_set+0x5b/0xa0 param_attr_store+0x93/0xe0 module_attr_store+0x1c/0x30 kernfs_fop_write_iter+0x116/0x1f0
Allocate and copy the replacement first, then replace the parameter value only after allocation succeeds.
Which versions are affected by CVE-2026-89552?
How do I fix CVE-2026-89552?
Apply the vendor's patch.
Is CVE-2026-89552 being exploited?
There is no known exploitation of CVE-2026-89552 in the wild and no public exploit code.
Sources
Also known as AZL-100830, BELL-CVE-2026-89552, DEBIAN-CVE-2026-89552, GHSA-gmqc-x8hx-2ggc, UBUNTU-CVE-2026-89552.