CVE-2026-43304 libceph: define and enforce CEPH_MAX_KEY_LEN
A buffer overflow in the Linux kernel's Ceph client allows attackers to execute arbitrary code or escalate privileges via crafted key material.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-43304?
CVE-2026-43304 is a critical memory corruption vulnerability in Linux kernel, published on 8 May 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: define and enforce CEPH_MAX_KEY_LEN
When decoding the key, verify that the key material would fit into a fixed-size buffer in process_auth_done() and generally has a sane length.
The new CEPH_MAX_KEY_LEN check replaces the existing check for a key with no key material which is a) not universal since CEPH_CRYPTO_NONE has to be excluded and b) doesn't provide much value since a smaller than needed key is just as invalid as no key -- this has to be handled elsewhere anyway.
Weakness: CWE-121
Which versions are affected by CVE-2026-43304?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-43304?
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-2026-43304 being exploited?
There is no known exploitation of CVE-2026-43304 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-43304, DEBIAN-CVE-2026-43304, GHSA-h4fr-xr6m-wwp8, ROOT-OS-DEBIAN-11-CVE-2026-43304, ROOT-OS-UBUNTU-2204-CVE-2026-43304, ROOT-OS-UBUNTU-2404-CVE-2026-43304 and 1 more.