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VulnerabilityPublished

CVE-2025-53940: TryQuiet quiet · Timing Side Channel

Affects TryQuiet quietSource CVE Database V5

0

Not known to be exploited · CVSS 8.5 High : upgrade to 6.0.1 soon.

Data as of 26 Oct 2026, 10:12 UTC

CVSS 4.0 base score
8.5High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
4.1% chance of exploitation in 30 days – higher than 90% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 6.0.1
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

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 24 Jul 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade tryquiet/quiet to 6.0.1.

Affected software

ProductAffectedFixed in
GitHubtryquiet/quietpkg:github/tryquiet/quietOther threatsAffected
  • <6.0.1
Fixed in
  • 6.0.1

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Beyond the essential step of upgrading to Quiet version 6.0.1 or later, European organizations should implement several targeted mitigations: 1) Conduct a thorough inventory to identify all instances of Quiet in use, including alpha and pre-release versions, to ensure no vulnerable deployments remain. 2) Restrict local access to systems running Quiet to trusted users only, employing strict access controls and monitoring to detect suspicious activities indicative of timing attacks. 3) Implement network segmentation and application-layer firewalls to limit exposure of the Quiet API endpoints, reducing the attack surface. 4) Employ anomaly detection tools that can identify unusual timing patterns or repeated token verification attempts that may indicate an ongoing timing attack. 5) Educate developers and security teams about the risks of non-constant-time comparisons in authentication mechanisms to prevent similar vulnerabilities in custom or third-party software. 6) Regularly review and update cryptographic and authentication libraries to ensure they use constant-time operations where applicable. 7) In environments where upgrading is delayed, consider deploying compensating controls such as multi-factor authentication or additional token validation layers to reduce the risk of token compromise.

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.

References

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