CVE-2026-59828 Discourse: Hidden post revisions leak through adjacent visible diffs
Attackers can view hidden post revisions by exploiting visible diffs on adjacent revisions, leaking sensitive content to unauthorized users.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-59828?
CVE-2026-59828 is a medium-severity vulnerability in Discourse Discourse, published on 9 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
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.
Weakness: CWE-200
Which versions are affected by CVE-2026-59828?
1 open source package ship an affected version, including discourse. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
discourse Bitnami | From 2026.1.0 | 2026.1.5, 2026.4.2, 2026.5.1, 2026.7.0 |
Products include Discourse Discourse.
How do I fix CVE-2026-59828?
Upgrade discourse to a fixed version for your release line: 2026.1.5, 2026.4.2, 2026.5.1 or 2026.7.0.
Is CVE-2026-59828 being exploited?
There is no known exploitation of CVE-2026-59828 in the wild and no public exploit code.
Other vulnerabilities in Discourse Discourse
- CVE-2021-41163 RCE via malicious SNS subscription payload
- CVE-2022-36066 Discourse vulnerable to RCE via admins uploading maliciously zipped file
- CVE-2022-39356 Discourse user account takeover via email and invite link
- CVE-2023-22468 Discourse vulnerable to Cross-site Scripting in local oneboxes
- CVE-2026-27934 Discourse leaks private topic title and post excerpt via user action API endpoint
Sources
Also known as BIT-discourse-2026-59828, GHSA-q456-4f8q-42vx.