CVE-2026-34975 Details
Description
Plunk is an open-source email platform built on top of AWS SES. Prior to 0.8.0, a CRLF header injection vulnerability was discovered in SESService.ts, where user-supplied values for from.name, subject, custom header keys/values, and attachment filenames were interpolated directly into raw MIME messages without sanitization. An authenticated API user could inject arbitrary email headers (e.g. Bcc, Reply-To) by embedding carriage return/line feed characters in these fields, enabling silent email forwarding, reply redirection, or sender spoofing. The fix adds input validation at the schema level to reject any of these fields containing \r or \n characters, consistent with the existing validation already applied to the contentId field. This vulnerability is fixed in 0.8.0.
A CRLF header injection vulnerability exists in Plunk versions prior to 0.8.0, specifically within the SESService.ts file. This vulnerability allows authenticated API users to inject arbitrary email headers by embedding carriage return/line feed characters into user-supplied fields such as 'from.name', 'subject', custom header keys/values, and attachment filenames. The injected headers could enable silent email forwarding, reply redirection, or sender spoofing. The issue arises because user input is directly interpolated into raw MIME messages without proper sanitization.
Users can upgrade to Plunk version 0.8.0 or later, where this vulnerability has been addressed by adding input validation to reject carriage return and line feed characters in the affected fields.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Apr 7, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/useplunk/plunk/security/advisories/GHSA-2mvm-rg5v-7hfq | [email protected] | Vendor Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-93 | Improper Neutralization of CRLF Sequences ('CRLF Injection') | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| useplunk plunk | < 0.8.0 |
CPE
Remediation
| |
Change History
4 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| Apr 22, 2026 | Initial Analysis | [email protected] |
| Apr 6, 2026 | New CVE Received | [email protected] |