All vulnerabilities

Servers and applications

CVE-2026-26078

Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, when the `patreon_webhook_secret` site setting is blank, an attacker can forge valid webhook signatures by computing an HMAC-MD5 with an empty string as the key. Since the request body is known to the sender, the attacker can produce a matching signature and send arbitrary webhook payloads. This…

Severity
High 7.5
Published
26 Feb 2026
Last changed
17 Jun 2026
Added to UpHeron
21 Oct 2026
Fixed in
2025.12.0, 2026.1.1
Sources
NVD

Affected software

SoftwareAffected versions
DiscourseServers and applications · cpe:a:discourse:discourse
  • Every version before 2025.12.0
  • From 2026.1.0 before 2026.1.1
  • Version 2026.2.0

References

  • NVD https://nvd.nist.gov/vuln/detail/CVE-2026-26078
  • CVE.org https://www.cve.org/CVERecord?id=CVE-2026-26078