CVE-2025-53940 HIGH

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

Vendor Tryquiet
Product quiet
Weakness CWE-208
Published July 24, 2025
Last update July 25, 2025

CVSS base score

8.5/10
Attack vector Local
Attack complexity High
Privileges required Low
User interaction None
Confidentiality
Integrity

CVSS vector

CVSS:4.0/AV:L/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:N/SA:N

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

July 24, 2025 CVE published
July 25, 2025 Record updated