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

> An authenticated user can trigger Server-Side Request Forgery in Novu by supplying malicious chat webhook URLs, allowing access to internal network services.

- **Severity:** Medium 5.3 (`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`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 22 Sep 2026
- **Updated:** 25 Sep 2026
- **Also known as:** GHSA-pg9q-8v57-hqph

## What is CVE-2026-75511?

CVE-2026-75511 is a medium-severity server-side request forgery vulnerability in @novu api-service, published on 22 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### 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.

Weakness: CWE-918 (Server-Side Request Forgery)

## Which versions are affected by CVE-2026-75511?


## How do I fix CVE-2026-75511?

No fix has been published for CVE-2026-75511 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-75511 being exploited?

There is no known exploitation of CVE-2026-75511 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-75511 and fix it if it is affected.

What it is: CVE-2026-75511 is a medium-severity server-side request forgery vulnerability in @novu api-service, published on 22 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-75511 in the wild and no public exploit code.

Affected product: @novu api-service. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-75511/ (Markdown: https://insights.sbomify.com/CVE-2026-75511/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-75511
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-75511
- OSV: https://osv.dev/vulnerability/CVE-2026-75511

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-75511/
Summaries are generated and may contain mistakes; the official description above is the record.