CVE-2026-26077 Details
Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, several webhook endpoints (SendGrid, Mailjet, Mandrill, Postmark, SparkPost) in the `WebhooksController` accepted requests without a valid authentication token when no token was configured. This allowed unauthenticated attackers to forge webhook payloads and artificially inflate user bounce scores, potentially causing legitimate user emails to be disabled. The Mailpace endpoint had no token validation at all. Starting in versions 2025.12.2, 2026.1.1, and 2026.2.0, all webhook endpoints reject requests with a 406 response when no authentication token is configured. As a workaround, ensure that webhook authentication tokens are configured for all email provider integrations in site settings (e.g., `sendgrid_verification_key`, `mailjet_webhook_token`, `postmark_webhook_token`, `sparkpost_webhook_token`). There's no current workaround for mailpace before getting this fix.
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Exploit prediction scoring system (EPSS) score for CVE-2026-26077
EPSS (Exploit Prediction Scoring System): EPSS predicts the likelihood that a vulnerability will be exploited in the wild. A higher percentage means a greater chance of an exploit occurring. The EPSS model produces a probability score between 0 and 1 (0 and 100%).
0.1 Probability of exploitation activity being observed over the next 30 days (27th percentile)
CVSS score for CVE-2026-26077
CVSS (Common Vulnerability Scoring System): An open framework owned and managed by FIRST.Org, Inc. that assigns a numerical score from 0 to 10 to software vulnerabilities to indicate their severity.
6.5 Medium
Products affected by CVE-2026-26077
Discourse 1.8.0
Discourse 1.8.1
Discourse 1.8.3
Discourse 1.9.0
Discourse 2.0.0
DVE Score by Bitsight AI
DVE scores complement traditional static scoring systems like CVSS with Bitsight AI powered real-time threat intelligence and underground cyber criminal activity so that security teams can reduce alert fatigue and focus on vulnerabilities most likely to be exploited.
Low
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CVE-2026-26077 Global Footprint

Top 10 Identified Countries

Country Observations Percentage
US 901 48.23%
DE 244 13.06%
NL 103 5.51%
FR 82 4.39%
GB 79 4.23%
SG 71 3.80%
CA 51 2.73%
CN 40 2.14%
JP 33 1.77%
IN 32 1.71%

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CVE-2026-26077 Industry Footprint

Top 10 Identified Industries

*Service provider organizations (typically Technology and Telecommunications) are disproportionally represented in the results given their upstream ownership of end-user infrastructure. See our FAQs.

Industry* Observations Percentage
Technology 1,586 96.18%
Education 20 1.21%
Telecommunications 16 0.97%
Government/Politics 9 0.55%
Business Services 5 0.30%
Finance 3 0.18%
Retail 3 0.18%
Nonprofit/NGO 3 0.18%
Insurance 2 0.12%
Engineering 2 0.12%

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