CVE-2026-89556 module: validate string table section types
A missing validation in the Linux kernel module loader allows out-of-bounds memory access, potentially leading to code execution or privilege escalation.
- 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-2026-89556?
CVE-2026-89556 is a memory corruption 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:
module: validate string table section types
In elf_validity_cache_sechdrs, section sizes and offsets are validated, unless the section type is SHT_NULL or SHT_NOBITS.
Later, elf_validity_cache_secstrings and elf_validity_cache_index_str access the section name table (.shstrtab) and symbol string table (.strtab) headers without first ensuring that their types are SHT_STRTAB. If a section type is SHT_NULL or SHT_NOBITS, sh_offset has not been validated and may reference out-of-bounds memory when dereferenced in elf_validity_cache_secstrings or elf_validity_cache_strtab.
Validate that both string section headers are of type SHT_STRTAB before caching them.
Which versions are affected by CVE-2026-89556?
How do I fix CVE-2026-89556?
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-2026-89556 being exploited?
There is no known exploitation of CVE-2026-89556 in the wild and no public exploit code.
Sources
Also known as AZL-100737, BELL-CVE-2026-89556, DEBIAN-CVE-2026-89556, GHSA-whm7-hr5x-2m9w, UBUNTU-CVE-2026-89556.