# CVE-2026-93850: Mattermost denial of service via PDF text extraction memory exhaustion

Source: https://junglewise.ai/threats/cve-2026-93850-mattermost-versions-11-9-x-11-9-1-11-8-x-11-8-5-11-7-x-11-7-10-11  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-26. Updated: 2026-10-26  
License: CC BY 4.0 with a link back

CVE-2026-93850 · Severity: medium · CVSS 6.5 · Published 2026-10-26

Mattermost, a team collaboration platform, contains a vulnerability in how it processes uploaded PDF files. An authenticated user can upload a specially crafted PDF that appears small but expands to enormous size when decompressed, exhausting server memory and causing the service to become unavailable to all users.

Technologies: [Mattermost Server](https://junglewise.ai/threats/technologies/server-public). Vendors: [Mattermost](https://junglewise.ai/threats/vendors/mattermost).

## Quick answers

**Is CVE-2026-93850 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-93850 being exploited in the wild.

**How severe is CVE-2026-93850?** Medium severity, with a CVSS score of 6.5, published 26 October 2026.

**Which products and versions are affected?** Mattermost Server 11.7.x through 11.7.10, 11.8.x through 11.8.5, 11.9.x through 11.9.1, 11.10.x through 11.10.1.

**Is there a fix for CVE-2026-93850?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-93850 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-93850?** Check whether you run Mattermost Server at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability exists in the PDF text extraction component which fails to properly bound memory allocation when decompressing PDF content streams. An authenticated attacker can upload a maliciously crafted PDF with highly compressed content that expands to a very large amount of text, causing server memory exhaustion and denial of service. Exploitation requires authentication and user interaction (file upload) but no network access beyond the application itself.

## Affected products

- Mattermost Mattermost Server 11.7.x through 11.7.10, 11.8.x through 11.8.5, 11.9.x through 11.9.1, 11.10.x through 11.10.1

## Timeline

- 2026-10-26: disclosed

## References

- [https://mattermost.com/security-updates](https://mattermost.com/security-updates)

## Related threats

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