# 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.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 11 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-100737, BELL-CVE-2026-89556, DEBIAN-CVE-2026-89556, GHSA-whm7-hr5x-2m9w, UBUNTU-CVE-2026-89556

## 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.

## Is CVE-2026-89556 being exploited?

There is no known exploitation of CVE-2026-89556 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-89556 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-89556 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-89556/ (Markdown: https://insights.sbomify.com/CVE-2026-89556/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-89556
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-89556
- OSV: https://osv.dev/vulnerability/CVE-2026-89556

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-89556/
Summaries are generated and may contain mistakes; the official description above is the record.