What is CVE-2025-53102?

CVE-2025-53102 is a critical-severity vulnerability in Discourse, classified under Session Fixation. CVSS score: 9.8/10. Published 2025-07-29.

How severe is CVE-2025-53102?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Vulnerability in Discourse

CVE-2025-53102

Discourse is an open-source community discussion platform. Prior to version 3.4.7 on the `stable` branch and version 3.5.0.beta.8 on the `tests-passed` branch, upon issuing a physical security key for 2FA, the server generates a WebAuthn challenge, which the client signs. The challenge is not cleared from the user’s session after authentication, potentially allowing reuse and increasing security risk. This is fixed in versions 3.4.7 and 3.5.0.beta.8.

Published 2025-07-29 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.005 (38.3th percentile), scored 2026-10-01.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 38th percentile — 38.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: +0.000

Affected products

Discourse — versions >= 3.5.0.beta1, < 3.5.0.beta.8, 3.5.0, < 3.4.7

Weakness classification (CWE)

CWE-384 — Session Fixation

References

github.com/discourse/discourse/security/advisories/GHSA-hv49-93h5-4wcv (Third Party Advisory)
github.com/discourse/discourse/commit/20bf65099bb861a141bc10e8a4eab65329d91802 (Patch)
github.com/discourse/discourse/commit/8bc0cee2c00a514ea60f33ea6172da2ce5a05beb (Patch)

Frequently asked questions

What is CVE-2025-53102?: CVE-2025-53102 is a critical-severity vulnerability in Discourse, classified under Session Fixation. CVSS score: 9.8/10. Published 2025-07-29.
How severe is CVE-2025-53102?: Critical severity. CVSS v3 base score is 9.8 out of 10.