CVE-2026-80558 libceph: Avoid using invalid osd indices from primary_temp
A missing bounds check in the Linux kernel Ceph client allows out-of-bounds memory access via corrupted OSD maps, potentially causing crashes or code execution.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-80558?
CVE-2026-80558 is a critical memory corruption vulnerability in Linux, published on 26 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
libceph: Avoid using invalid osd indices from primary_temp
A corrupted osdmap received from a Ceph monitor or OSD may contain osd indices in its pg_temp, primary_temp, pg_upmap, and pg_upmap_items parts that don't exist, i.e., that are greater than max_osd or smaller than CEPH_HOMELESS_OSD (-1). These indices are used to create the up and acting set in ceph_pg_to_up_acting_osds(), called from calc_target(). While most of these osd indices are checked, the one from primary_temp is not. Subsequently, this may lead to calc_target() returning this (potentially invalid) index as target osd for a (linger) request. Because the osd_state, osd_weight, and osd_addr arrays only contain max_osd entries (with indices 0 to max_osd -1), this leads to out-of-bounds accesses when trying to read values from these arrays.
This patch fixes the issue by adding a check to get_temp_osds(), so that only valid osd indices from primary_temp are used, and it falls back to using the primary from pg_temp or the up set if it is invalid.
[ idryomov: changelog ]
Which versions are affected by CVE-2026-80558?
How do I fix CVE-2026-80558?
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-2026-80558 being exploited?
There is no known exploitation of CVE-2026-80558 in the wild and no public exploit code.
Sources
Also known as AZL-97721, BELL-CVE-2026-80558, DEBIAN-CVE-2026-80558, GHSA-qr98-rr7x-25v7, UBUNTU-CVE-2026-80558.