Quick answers
- Is CVE-2026-8075 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-8075 being exploited in the wild.
- How severe is CVE-2026-8075?
- Medium severity, with a CVSS score of 6.5, published 17 July 2026.
- Which products and versions are affected?
- Mattermost Desktop App <=6.2, 5.5.13, 6.0.2.0.
- Is there a fix for CVE-2026-8075?
- 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-2026-8075 attacked?
- It is attacked over the network, in a network appliance.
- Am I affected by CVE-2026-8075?
- Check whether you run Mattermost Desktop App 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 Mattermost Desktop App suffers from an improper check for unusual or exceptional conditions (CWE-754) specifically related to a missing null check during header validation. An authenticated attacker can exploit this by posting a malicious link with an embedded image that lacks specific expected headers. When other channel members' desktop clients attempt to process the image, the lack of a null check causes the application to crash. This is a remote denial-of-service attack requiring low privileges (standard user account) and no user interaction beyond the client attempting to render the malicious post. Fixes are available in versions 6.3.0, 5.13.6.0, and 6.2.1.0.
Affected products
- Mattermost Mattermost Desktop App <=6.2, 5.5.13, 6.0.2.0
Timeline
- 2026-07-17: advisory: Mattermost Advisory MMSA-2026-00668 published.
- 2026-07-17: disclosed: CVE-2026-8075 published to the NVD.