CVE-2026-53961 Discourse: Forged AWS SNS bounce notifications can disable a targeted user's email (missing TopicArn binding)
Attackers can forge AWS SNS bounce notifications to disable targeted user emails, potentially leading to account takeover or denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-53961?
CVE-2026-53961 is a medium-severity missing authorization 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, the AWS SES bounce webhook at POST /webhooks/aws verified that SNS messages were signed by Amazon but did not bind them to trusted TopicArn values, allowing any AWS account holder to publish validly signed forged Bounce notifications that revoke a targeted user email. This issue is fixed in versions 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5.
Weakness: CWE-345
Which versions are affected by CVE-2026-53961?
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 |
Products include Discourse Discourse.
How do I fix CVE-2026-53961?
Upgrade discourse to a fixed version for your release line: 2026.1.5, 2026.4.2 or 2026.5.1.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-53961 being exploited?
There is no known exploitation of CVE-2026-53961 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-2026-53961, GHSA-8f9m-v436-wr3x.