CVE-2026-26078Discourse is an open source discussion platform.

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 allows unauthorized creation, modification, or deletion of Patreon pledge data and triggering patron-to-group synchronization. This vulnerability is patched in versions 2025.12.2, 2026.1.1, and 2026.2.0. The fix rejects webhook requests when the webhook secret is not configured, preventing signature forgery with an empty key. As a workaround, configure the `patreon_webhook_secret` site setting with a strong, non-empty secret value. When the secret is non-empty, an attacker cannot forge valid signatures without knowing the secret.

CVSS

7.5 HIGH (v3.1, NVD)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Weakness (CWE)

CWE-639

Known exploited

Not in CISA's KEV catalog

EPSS (exploitation in the next 30 days)

Not loaded for this CVE

Assigned by

Not given

NVD analysis

Analyzed

Record last updated

Jun 17, 2026

First seen by InfoSec Signals

Oct 9, 2026

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.