Medium 6.5Published Jul 9, 2026

CVE-2026-53961Discourse: Forged AWS SNS bounce notifications can disable a targeted user's email (missing TopicArn binding)

Updated under an hour ago (Oct 28, 2026, 2:50 AM ET)

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No exploitation reported and no EPSS estimate yet.

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Exploited in the last 30 days

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: 6.5 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L
Weakness (CWE): CWE-345
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Analyzed
Record last updated: Jul 10, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

discourse discourse discourse:discourse (from the name)	from 2026.5.0-latest, < 2026.5.1; from 2026.4.0-latest, < 2026.4.2; from 2026.1.0-latest, < 2026.1.5	CNA record
discourse discourse discourse:discourse	from 2026.1.0 before 2026.1.5; from 2026.4.0 before 2026.4.2; from 2026.5.0 before 2026.5.1; 2026.6.0	NVD

References

References

https://github.com/discourse/discourse/security/advisories/GHSA-8f9m-v436-wr3x	x-refsource-confirm, vendor-advisory
https://github.com/discourse/discourse/commit/3a3d315a85ef3c6aabfc7e7bb38702059784f06b	x-refsource-misc, patch
https://github.com/discourse/discourse/commit/61f12e13aa1b760f81d5ff60f12e3a7e77434b94	x-refsource-misc, patch
https://github.com/discourse/discourse/commit/958f0cd831d65a49ec75f05343ca2c167679f0ea	x-refsource-misc, patch
https://github.com/discourse/discourse/commit/aea35190791261bab258ebab05da279e78cdd0e6	x-refsource-misc, patch
https://github.com/discourse/discourse/releases/tag/v2026.1.5	x-refsource-misc, release-notes
https://github.com/discourse/discourse/releases/tag/v2026.4.2	x-refsource-misc, release-notes
https://github.com/discourse/discourse/releases/tag/v2026.5.1	x-refsource-misc, release-notes
https://github.com/discourse/discourse/releases/tag/v2026.6.0	x-refsource-misc, release-notes

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.