CVE-2025-54499: Insecure string comparison enables timing attacks

Severity: low (CVSS 3.7 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-10-16 · updated 2026-10-19
Weakness: CWE-208

Description

Mattermost versions 10.5.x <= 10.5.10, 10.11.x <= 10.11.2 fail to use constant-time comparison for sensitive string comparisons which allows attackers to exploit timing oracles to perform byte-by-byte brute force attacks via response time analysis on Cloud API keys and OAuth client secrets

Affected products

Mattermost: from 10.5.0 before 10.5.11; from 10.11.0 before 10.11.3 — fixed in 10.11.3, 10.5.11

How to fix

Upgrade to a fixed version: Mattermost 10.11.3, 10.5.11. Check the vendor advisory for mitigations.

References

https://mattermost.com/security-updates

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