CVE-2026-80639 cxl/test: Fix __fortify_panic
A false positive buffer overflow check in the CXL test module causes a kernel panic, leading to local denial of service.
- 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-2026-80639?
CVE-2026-80639 is a denial of service 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:
cxl/test: Fix __fortify_panic
Fix a runtime assertion in setup_xor_mapping(). Fortify complains that it is potentially overflowing the xormaps array per __counted_by(nr_maps). Quiet the false positive by initializing @nr_maps earlier.
memcpy: detected buffer overflow: 32 byte write of buffer size 0 WARNING: lib/string_helpers.c:1036 at __fortify_report+0x4d/0xa0, CPU#8: modprobe/2728 Call Trace: __fortify_panic+0xd/0xf setup_xor_mapping+0x6c/0xa0 [cxl_translate]
[ dj: Fixed up @nr_entries to @nr_maps in commit log. ]
Which versions are affected by CVE-2026-80639?
How do I fix CVE-2026-80639?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-80639 being exploited?
There is no known exploitation of CVE-2026-80639 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-80639, GHSA-gm6m-26p9-v4r9, UBUNTU-CVE-2026-80639.