# CVE-2026-26077: Discourse doesn't ensure webhooks require a token

> Unauthenticated attackers can forge webhook payloads to inflate user bounce scores, disabling legitimate user emails in Discourse.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 26 Feb 2026
- **Updated:** 27 Feb 2026
- **Also known as:** BIT-discourse-2026-26077, GHSA-j67c-53j2-4hfw

## What is CVE-2026-26077?

CVE-2026-26077 is a medium-severity missing authorization vulnerability in Discourse Discourse, published on 26 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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.

Weakness: CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2026-26077?

1 open source package ship an affected version, including discourse. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `discourse` | Bitnami | All versions | 2025.12.2, 2026.1.1 |

Products: Discourse Discourse.

## How do I fix CVE-2026-26077?

Upgrade discourse to a fixed version for your release line: 2025.12.2 or 2026.1.1.

## Is CVE-2026-26077 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-26077 exists.

Public exploit code:

- Discourse - Unauthenticated Mailpace Webhook Bounce-Score Forgery (nuclei): http/cves/2026/CVE-2026-26077.yaml

## Other vulnerabilities in Discourse Discourse

- [CVE-2021-41163](https://insights.sbomify.com/CVE-2021-41163/): RCE via malicious SNS subscription payload (critical 10.0)
- [CVE-2022-36066](https://insights.sbomify.com/CVE-2022-36066/): Discourse vulnerable to RCE via admins uploading maliciously zipped file (critical 9.1)
- [CVE-2022-39356](https://insights.sbomify.com/CVE-2022-39356/): Discourse user account takeover via email and invite link (high 8.9)
- [CVE-2023-22468](https://insights.sbomify.com/CVE-2023-22468/): Discourse vulnerable to Cross-site Scripting in local oneboxes (high 8.8)
- [CVE-2026-27934](https://insights.sbomify.com/CVE-2026-27934/): Discourse leaks private topic title and post excerpt via user action API endpoint (high 8.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-26077 and fix it if it is affected.

What it is: CVE-2026-26077 is a medium-severity missing authorization vulnerability in Discourse Discourse, published on 26 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-26077 exists.

Affected packages and fixed versions:
- discourse (Bitnami): affected all versions; fixed in 2025.12.2, 2026.1.1

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-2026-26077/ (Markdown: https://insights.sbomify.com/CVE-2026-26077/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-26077
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-26077
- OSV: https://osv.dev/vulnerability/CVE-2026-26077

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-26077/
Summaries are generated and may contain mistakes; the official description above is the record.