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Vulnerability record · CVE-2026-53961 · published 9 July 2026

CVE-2026-53961: Discourse insufficient verification of data authenticity vulnerability

Discourse · Discourse

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.

6.5 CVSS 3.1 Medium EPSS 0.30% · top 79.5% CWE-345 · Insufficient verification of data authenticity
6.5CVSS 3.1 base score
0.30%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
9References
14 Jul 2026Last modified by NVD

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.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/discourse/discourse/commit/3a3d315a85ef3c6aabfc7e7bb38702059784f06b Patch
https://github.com/discourse/discourse/commit/61f12e13aa1b760f81d5ff60f12e3a7e77434b94 Patch
https://github.com/discourse/discourse/commit/958f0cd831d65a49ec75f05343ca2c167679f0ea Patch
https://github.com/discourse/discourse/commit/aea35190791261bab258ebab05da279e78cdd0e6 Patch
https://github.com/discourse/discourse/releases/tag/v2026.1.5 Release Notes
https://github.com/discourse/discourse/releases/tag/v2026.4.2 Release Notes
https://github.com/discourse/discourse/releases/tag/v2026.5.1 Release Notes
https://github.com/discourse/discourse/releases/tag/v2026.6.0 Release Notes
https://github.com/discourse/discourse/security/advisories/GHSA-8f9m-v436-wr3x Vendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2026-53961), CISA KEV, FIRST EPSS (scores of 2026-10-01). This page is refreshed as NVD updates the record.