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Vulnerability · Published Sep 22, 2026 · Assigned by GitHub_M

CVE-2026-75511Novu: Server-Side Request Forgery (SSRF) via Chat Provider Webhook URLs

Medium 5.3

In plain English

A medium-severity server-side request forgery in api-service from @novu. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 40% of all known vulnerabilities).

Severity (CVSS 4.0)5.3Medium
Exploit odds (30 days)0.5%top 59.6% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

Novu provides an API for sending notifications through multiple channels. Prior to 3.18.0, Novu accepts chat webhook URLs from subscriber credentials.webhookUrl, channel endpoint endpoint.url, event payload.webhookUrl, and event overrides.webhookUrl, then passes the selected endpoint.url through send-message-chat.usecase.ts to raw HTTP requests in the Slack, Discord, Mattermost, Microsoft Teams, Grafana On-Call, Ryver, Rocket.Chat, GetStream, and Zulip providers. An authenticated user can supply an internal or otherwise restricted destination because these paths do not apply normalizeOutboundHttpUrl, assertSafeOutboundUrl, or the DNS-pinned safeOutboundJsonRequest protection used by the generic webhook providers. The Novu worker can consequently issue attacker-directed POST requests to internal network services and cause interactions or actions supported by those services. This issue is fixed in version 3.18.0.

Affected products (as reported)

VendorProductVersions
novuhq novu < 3.18.0
@novu api-service < 3.18.0

Weakness: CWE-918 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:L/SI:L/SA:L

References