CVE-2026-53961CWE-345

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

Medium · published July 9, 2026

CVSS v3.1
6.5
EPSS
0%
Percentile
21.5
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
6.5 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L
CVSS v4.0
Not supplied
EPSS
0.00300 · 21.5th percentile
Weakness
CWE-345 · Insufficient Verification of Data Authenticity
Published
2026-07-09T21:48Z
EPSS history
Timeline
  • 09 JUL 21:48Z
    Discourse: Forged AWS SNS bounce notifications can disable a targeted user's email (missing TopicArn binding)
    cvelistv5