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Vulnerabilities

Vulnerability · CVE-2025-64528

Discourse is an open source discussion platform.

Published Dec 30, 2025 · catalog updated Dec 30, 2025 · Discourse is an open

Last checked Nov 2, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2025-64528. EPSS is 0.29%. Act only if a listed version of Discourse is an open is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (Discourse is an open).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
Medium6.3
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.29%
Remediation
Version ranges on file
Affected products
vendor discourse discourse < 3.5.3

Discourse is an open source discussion platform. Prior to versions 3.5.3, 2025.11.1, and 2025.12.0, an attacker who knows part of a username can find the user and their full name via UI or API, even when is disabled. Versions 3.5.3, 2025.11.1, and 2025.12.0 contain a fix.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • vendor discourse discourse < 3.5.3< 3.5.3

How to fix CVE-2025-64528

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2025-64528. EPSS is 0.29%. Act only if a listed version of Discourse is an open is installed.

Which versions are affected?

Compare what you have installed with discourse discourse < 3.5.3 < 3.5.3. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 0.29%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Dec 30, 2025 · EUVD

    Detected

    Discourse is an open source discussion platform. Prior to versions 3.5.3, 2025.11.1, and 2025.12.0, an attacker who knows part of a username can find the user and their full name via UI or API, even when is disabled. Versions 3.5.3, 2025.11.1, and 2025.12.0 contain a fix.

  2. Dec 30, 2025 · EUVD

    Updated

    Discourse is an open source discussion platform. Prior to versions 3.5.3, 2025.11.1, and 2025.12.0, an attacker who knows part of a username can find the user and their full name via UI or API, even when is disabled. Versions 3.5.3, 2025.11.1, and 2025.12.0 contain a fix.

Sources

  • CVE.orgVulnerability recordCVE-2025-64528

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2025-64528

    30-day exploitation probability 0.29%

    first.org
  • EUVDVulnerability recordEUVD-2025-205817

    Discourse is an open source discussion platform. Prior to versions 3.5.3, 2025.11.1, and 2025.12.0, an attacker who knows part of a username can find the user and their full name via UI or API, even when is disabled. Versions 3.5.3, 2025.11.1, and 2025.12.0 contain a fix.

    euvd.enisa.europa.eu

References

Freshness

Last verified in this catalog Nov 2, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • FIRST EPSSNov 2, 2026
  • CVE.orgNov 2, 2026
  • EUVDNov 1, 2026