PT-2026-56998 · Discourse · Discourse

Published 2026-07-09 · Updated 2026-07-09 · CVE-2026-53961

Mitre

CVSS v3.1

6.5

Medium

Base vector

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

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.

Fix

Insufficient Verification of Data Authenticity

Weakness Enumeration

CWE-345

Related Identifiers

CVE-2026-53961

Affected Products

Discourse

References · 10

• https://nvd.nist.gov/vuln/detail/CVE-2026-53961 · Security Note
• https://github.com/discourse/discourse/releases/tag/v2026.6.0 · Note
• https://github.com/discourse/discourse/commit/958f0cd831d65a49ec75f05343ca2c167679f0ea · Note
• https://github.com/discourse/discourse/releases/tag/v2026.5.1 · Note
• https://github.com/discourse/discourse/security/advisories/GHSA-8f9m-v436-wr3x · Note
• https://github.com/discourse/discourse/releases/tag/v2026.1.5 · Note
• https://github.com/discourse/discourse/commit/aea35190791261bab258ebab05da279e78cdd0e6 · Note
• https://github.com/discourse/discourse/commit/3a3d315a85ef3c6aabfc7e7bb38702059784f06b · Note
• https://github.com/discourse/discourse/commit/61f12e13aa1b760f81d5ff60f12e3a7e77434b94 · Note
• https://github.com/discourse/discourse/releases/tag/v2026.4.2 · Note