Discourse AWS SES Bounce Webhook Bypass <2026.6.0 via unbound SNS TopicArn
CVE-2026-53961 Published on July 9, 2026
Discourse: Forged AWS SNS bounce notifications can disable a targeted user's email (missing TopicArn binding)
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.
Vulnerability Analysis
CVE-2026-53961 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality, with no impact on integrity and availability.
Weakness Type
Insufficient Verification of Data Authenticity
The software does not sufficiently verify the origin or authenticity of data, in a way that causes it to accept invalid data.
Products Associated with CVE-2026-53961
Want to know whenever a new CVE is published for Discourse? stack.watch will email you.
Affected Versions
discourse:- Version >= 2026.5.0-latest, < 2026.5.1 is affected.
- Version >= 2026.4.0-latest, < 2026.4.2 is affected.
- Version >= 2026.1.0-latest, < 2026.1.5 is affected.