# CVE-2026-26824: Information disclosure in n/a

> Attackers can cause crashes or disclose information by processing crafted XLS files due to uninitialized memory in the libxls library.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 3 Jun 2026
- **Updated:** 23 Sep 2026
- **Also known as:** DEBIAN-CVE-2026-26824, GHSA-hwmf-9wj8-35pw, JLSEC-2026-1301, UBUNTU-CVE-2026-26824

## What is CVE-2026-26824?

CVE-2026-26824 is a medium-severity vulnerability in n/a, published on 3 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

libxls through version 1.6.3 contains a use of uninitialized memory vulnerability in the OLE container parser. Memory allocated for the Master Sector Allocation Table (MSAT) in read_MSAT() is not fully initialized before being consumed by ole2_validate_sector_chain(), which may result in application crashes or potential information disclosure when processing a crafted XLS file

Weakness: CWE-457 (Use of Uninitialized Variable)

## Which versions are affected by CVE-2026-26824?

It affects 1 product.


Products: Libxls Project Libxls.

## How do I fix CVE-2026-26824?

Upgrade to a fixed version.

## Is CVE-2026-26824 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-26824 exists.

## Other vulnerabilities in n/a

- [CVE-2017-2910](https://insights.sbomify.com/CVE-2017-2910/): Memory corruption in libxls (high 8.8)
- [CVE-2018-20452](https://insights.sbomify.com/CVE-2018-20452/): Use after free in n/a (high 8.8)
- [CVE-2017-12108](https://insights.sbomify.com/CVE-2017-12108/): Integer overflow in libxls (high 8.8)
- [CVE-2017-12109](https://insights.sbomify.com/CVE-2017-12109/): Integer overflow in libxls (high 8.8)
- [CVE-2017-12110](https://insights.sbomify.com/CVE-2017-12110/): Integer overflow in libxls (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-26824 and fix it if it is affected.

What it is: CVE-2026-26824 is a medium-severity vulnerability in n/a, published on 3 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-26824 exists.

Affected product: n/a. 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-2026-26824/ (Markdown: https://insights.sbomify.com/CVE-2026-26824/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-26824
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-26824
- OSV: https://osv.dev/vulnerability/CVE-2026-26824

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-26824/
Summaries are generated and may contain mistakes; the official description above is the record.