Skip to main content

Mondoo

Vulnerability Management
Technology
Services

Solutions

Financial Services
Manufacturing
Healthcare

Resources

Blog
Vulnerability Database
Documentation
GitHub

Company

About
Careers
Partners
Contact

Legal

Privacy
Terms
Imprint

© 2026 Mondoo, Inc.

Log in Get Assessment

Vulnerability IntelligenceCVE-2026-25783

CVE-2026-25783

MEDIUM4.3

Denial of service via malformed User-Agent header in getBrowserVersion

Published Mar 16, 2026

Modified 2 months ago

Details

Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fail to properly validate User-Agent header tokens which allows an authenticated attacker to cause a request panic via a specially crafted User-Agent header. Mattermost Advisory ID: MMSA-2026-00586

References

https://mattermost.com/security-updates

https://www.cve.org/CVERecord?id=CVE-2026-25783

CVSS Analysis

CVSS v3.1

4.3

Exploitability

Attack Vector

NetworkAV:N

Attack Complexity

LowAC:L

Privileges Required

LowPR:L

User Interaction

NoneUI:N

Scope

Scope

UnchangedS:U

Impact

Confidentiality

NoneC:N

Integrity

NoneI:N

Availability

LowA:L

4.3/CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

Weakness Type (CWE)

Other

Ecosystems

Timeline

PublishedMar 16, 2026

ModifiedMar 16, 2026

CVE-2026-25783 | Mondoo Vulnerability Intelligence