# CVE-2026-100242: DataTransfer depends on phpspreadsheet version vulnerable to CVE-2026-59933 (XLS/OLE memory exhaustion)

> Attackers can cause denial of service via excessive memory allocation in the DataTransfer extension due to a vulnerable dependency.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 29 Sep 2026
- **Updated:** 1 Oct 2026
- **Also known as:** GHSA-pc77-95w9-j7gj

## What is CVE-2026-100242?

CVE-2026-100242 is a high-severity denial of service vulnerability in Wikimedia Foundation Mediawiki - DataTransfer Extension, published on 29 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Dependency on Vulnerable Third-Party Component and Uncontrolled Resource Consumption vulnerability in Wikimedia Foundation Mediawiki - DataTransfer Extension allows Excessive Allocation.

This issue affects Mediawiki - DataTransfer Extension: from 1.46.0 before 1.47.0.

Weakness: CWE-400 (Uncontrolled Resource Consumption), CWE-1395 (Dependency on Vulnerable Third-Party Component)

## Which versions are affected by CVE-2026-100242?


## How do I fix CVE-2026-100242?

No fix has been published for CVE-2026-100242 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-100242 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-100242 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-100242 and fix it if it is affected.

What it is: CVE-2026-100242 is a high-severity denial of service vulnerability in Wikimedia Foundation Mediawiki - DataTransfer Extension, published on 29 Sep 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-2026-100242 exists.

Affected product: Wikimedia Foundation Mediawiki - DataTransfer Extension. 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-2026-100242/ (Markdown: https://insights.sbomify.com/CVE-2026-100242/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-100242
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-100242
- OSV: https://osv.dev/vulnerability/CVE-2026-100242

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-100242/
Summaries are generated and may contain mistakes; the official description above is the record.