# CVE-2026-23388: Squashfs: check metadata block offset is within range

> A corrupted Squashfs index can cause an out-of-bounds access in the Linux kernel, potentially leading to system crashes or arbitrary code execution.

- **Severity:** High 7.1 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 25 Mar 2026
- **Updated:** 15 Oct 2026
- **Also known as:** AZL-80601, BELL-CVE-2026-23388, DEBIAN-CVE-2026-23388, GHSA-3667-r4r3-59jh, ROOT-OS-DEBIAN-11-CVE-2026-23388, ROOT-OS-DEBIAN-12-CVE-2026-23388, ROOT-OS-DEBIAN-13-CVE-2026-23388, ROOT-OS-UBUNTU-2204-CVE-2026-23388, ROOT-OS-UBUNTU-2404-CVE-2026-23388, UBUNTU-CVE-2026-23388

## What is CVE-2026-23388?

CVE-2026-23388 is a high-severity memory corruption vulnerability in Linux kernel, published on 25 Mar 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:

Squashfs: check metadata block offset is within range

Syzkaller reports a "general protection fault in squashfs_copy_data"

This is ultimately caused by a corrupted index look-up table, which
produces a negative metadata block offset.

This is subsequently passed to squashfs_copy_data (via
squashfs_read_metadata) where the negative offset causes an out of bounds
access.

The fix is to check that the offset is within range in
squashfs_read_metadata.  This will trap this and other cases.

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2026-23388?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-23388?

Apply the vendor's patch.

## Is CVE-2026-23388 being exploited?

There is no known exploitation of CVE-2026-23388 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-23388 and fix it if it is affected.

What it is: CVE-2026-23388 is a high-severity memory corruption vulnerability in Linux kernel, published on 25 Mar 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-2026-23388 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2026-23388/ (Markdown: https://insights.sbomify.com/CVE-2026-23388/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-23388
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-23388
- OSV: https://osv.dev/vulnerability/CVE-2026-23388

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-23388/
Summaries are generated and may contain mistakes; the official description above is the record.