Information disclosure in Discourse

CVE-2026-59828

Discourse is an open-source discussion platform. Prior to 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5, post revisions that should be hidden from regular users could be leaked through visible diffs on adjacent revisions serialized by PostRevisionSerializer. This issue is fixed in versions 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5.

Vulnerability class: Information Disclosure

Published · last modified .

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N.

EPSS exploit prediction

EPSS: 0.005 (44.0th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 44th percentile — 44.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-59828: held from 0.005 to 0.005.

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

Affected products

  • Discourse — versions >= 2026.5.0-latest, < 2026.5.1, >= 2026.4.0-latest, < 2026.4.2, 2026.6.0

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-59828?
CVE-2026-59828 is a medium-severity vulnerability in Discourse, classified under Information Disclosure. CVSS score: 5.3/10. Published 2026-07-09.
How severe is CVE-2026-59828?
Medium severity. CVSS v3 base score is 5.3 out of 10.