CVE-2026-52958 libceph: Fix potential out-of-bounds access in osdmap_decode()
A corrupted Ceph OSD map message can trigger an out-of-bounds memory access in the Linux kernel, potentially leading to system crashes or arbitrary 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-2026-52958?
CVE-2026-52958 is a critical memory corruption vulnerability in Linux kernel, published on 24 Jun 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: Fix potential out-of-bounds access in osdmap_decode()
When decoding osd_state and osd_weight from an incoming osdmap in osdmap_decode(), both are decoded for each osd, i.e., map->max_osd times. The ceph_decode_need() check only accounts for sizeof(*map->osd_weight) once. This can potentially result in an out-of-bounds memory access if the incoming message is corrupted such that the max_osd value exceeds the actual content of the osdmap message.
This patch fixes the issue by changing the corresponding part in the ceph_decode_need() check to account for map->max_osd*sizeof(*map->osd_weight).
Weakness: CWE-125
Which versions are affected by CVE-2026-52958?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-52958?
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-2026-52958 being exploited?
There is no known exploitation of CVE-2026-52958 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-52958, DEBIAN-CVE-2026-52958, GHSA-xhq7-864q-xxj8, ROOT-OS-DEBIAN-11-CVE-2026-52958, ROOT-OS-DEBIAN-12-CVE-2026-52958, ROOT-OS-UBUNTU-2204-CVE-2026-52958 and 2 more.