Vulnerability Details CVE-2026-53961
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.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.002
EPSS Ranking 12.6%
CVSS Severity
CVSS v3 Score 6.5
References
- https://github.com/discourse/discourse/commit/3a3d315a85ef3c6aabfc7e7bb38702059784f06b
- https://github.com/discourse/discourse/commit/61f12e13aa1b760f81d5ff60f12e3a7e77434b94
- https://github.com/discourse/discourse/commit/958f0cd831d65a49ec75f05343ca2c167679f0ea
- https://github.com/discourse/discourse/commit/aea35190791261bab258ebab05da279e78cdd0e6
- https://github.com/discourse/discourse/releases/tag/v2026.1.5
- https://github.com/discourse/discourse/releases/tag/v2026.4.2
- https://github.com/discourse/discourse/releases/tag/v2026.5.1
- https://github.com/discourse/discourse/releases/tag/v2026.6.0
- https://github.com/discourse/discourse/security/advisories/GHSA-8f9m-v436-wr3x
Products affected by CVE-2026-53961
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cpe:2.3:a:discourse:discourse:2026.1.0
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cpe:2.3:a:discourse:discourse:2026.1.1
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cpe:2.3:a:discourse:discourse:2026.1.2
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cpe:2.3:a:discourse:discourse:2026.1.3
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cpe:2.3:a:discourse:discourse:2026.1.4
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cpe:2.3:a:discourse:discourse:2026.4.0
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cpe:2.3:a:discourse:discourse:2026.4.1
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cpe:2.3:a:discourse:discourse:2026.6.0