What’s Vulnerable › Vulnerabilities

CVE-2025-53940: Quiet uses insecure, inconsistent verification on local backend token

• Severity: high (CVSS 8.5 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 4.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2025-07-24 · updated 2026-06-17
• Weakness: CWE-208

Description

Quiet is an alternative to team chat apps like Slack, Discord, and Element that does not require trusting a central server or running one's own. In versions 6.1.0-alpha.4 and below, Quiet's API for backend/frontend communication was using an insecure, not constant-time comparison function for token verification. This allowed for a potential timing attack where an attacker would try different token values and observe tiny differences in the response time (wrong characters fail faster) to guess the whole token one character at a time. This is fixed in version 6.0.1.

Affected products

• TryQuiet quiet: before 6.0.1

References

• https://github.com/TryQuiet/quiet/issues/2820#issue-3021080269
• https://github.com/TryQuiet/quiet/pull/2928
• https://github.com/TryQuiet/quiet/security/advisories/GHSA-gpw8-w78h-xj67

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