# CVE-2026-57511: SuperPlane < 0.30.0 SMTP Header Injection via Webhook Event Title

> Unauthenticated attackers can inject SMTP headers via webhook titles to exfiltrate data or bypass email security checks in SuperPlane.

- **Severity:** Medium 6.3 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 28 Jul 2026
- **Updated:** 29 Jul 2026
- **Also known as:** GHSA-c3mp-rj38-mpvh

## What is CVE-2026-57511?

CVE-2026-57511 is a medium-severity vulnerability in superplanehq superplane, published on 28 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

SuperPlane before 0.30.0 contains an SMTP header injection vulnerability that allows unauthenticated attackers to inject arbitrary SMTP headers by including CRLF sequences in the event payload title field delivered via webhook. Attackers can manipulate the unsanitized title field passed to the SMTP DATA command to add Bcc recipients for content exfiltration, forge the From address to bypass SPF and DKIM checks, or inject Content-Type and MIME boundary headers to corrupt message bodies for phishing.

Weakness: CWE-93 (Improper Neutralization of CRLF Sequences)

## Which versions are affected by CVE-2026-57511?


## How do I fix CVE-2026-57511?

No fix has been published for CVE-2026-57511 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-57511 being exploited?

There is no known exploitation of CVE-2026-57511 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-57511 and fix it if it is affected.

What it is: CVE-2026-57511 is a medium-severity vulnerability in superplanehq superplane, published on 28 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-57511 in the wild and no public exploit code.

Affected product: superplanehq superplane. 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-2026-57511/ (Markdown: https://insights.sbomify.com/CVE-2026-57511/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-57511
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-57511
- OSV: https://osv.dev/vulnerability/CVE-2026-57511

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-57511/
Summaries are generated and may contain mistakes; the official description above is the record.