CVE-2026-57511

SuperPlane < 0.30.0 SMTP Header Injection via Webhook Event Title

MEDIUM
5.4
CVSS Score
Published: July 28, 2026 at 07:09 PM UTC
Updated: October 23, 2026 at 11:10 PM UTC
1 product affected across 1 vendorSuperPlane

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Severity
MEDIUM5.4
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

0 ≤ v < 0.30.00
Affected range stops below 0.30.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.4MEDIUMVulnCheck
Attack Vector
NETWORK
Complexity
HIGH
Privileges
NONE
User Interaction
NONE
Scope
CHANGED
Confidentiality
LOW
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-93

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