Vulnerability · Published Jul 9, 2026 · Assigned by GitHub_M

CVE-2026-59828Discourse: Hidden post revisions leak through adjacent visible diffs

Medium 5.3

In plain English

A medium-severity information exposure in discourse from discourse. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 46% of all known vulnerabilities).

Severity (CVSS 3.1)5.3Medium
Exploit odds (30 days)0.5%top 54.1% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

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.

Affected products (as reported)

VendorProductVersions
discourse discourse >= 2026.1.0-latest, < 2026.1.5>= 2026.4.0-latest, < 2026.4.2>= 2026.5.0-latest, < 2026.5.1

Weakness: CWE-200 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

References