CVE-2025-48053 Discourse vulnerable to DoS via large URL payload in PM to a bot
Attackers can cause denial of service by sending malicious URLs in private messages to bot users, affecting Discourse forum availability.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-48053?
CVE-2025-48053 is a high-severity denial of service vulnerability in Discourse Discourse, published on 9 Jun 2025. 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 version 3.4.4 of the `stable` branch, version 3.5.0.beta5 of the `beta` branch, and version 3.5.0.beta6-dev of the `tests-passed` branch, sending a malicious URL in a PM to a bot user can cause a reduced the availability of a Discourse instance. This issue is patched in version 3.4.4 of the `stable` branch, version 3.5.0.beta5 of the `beta` branch, and version 3.5.0.beta6-dev of the `tests-passed` branch. No known workarounds are available.
Which versions are affected by CVE-2025-48053?
1 open source package ship an affected version, including discourse. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
discourse Bitnami | All versions | 3.4.4 |
Products include Discourse Discourse.
How do I fix CVE-2025-48053?
Upgrade discourse to 3.4.4 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2025-48053 being exploited?
There is no known exploitation of CVE-2025-48053 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-2025-48053, GHSA-3q5q-qmrm-rvwx.