CVE-2026-34975

MEDIUM
MEDIUM Priority: 0.01 BB Relevance: 59/100
Published: 2026-04-06 Modified: 2026-10-24 First seen: 2026-10-29 Status: active

Attack Surface

Network Low Complexity No Interaction

CVSS Vector Breakdown

AV: Network
AC: Low
PR: Low
UI: None
S: Unchanged
C: None
I: Low
A: None

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.

Weakness Classification (1)

Affected Software (1)

VendorProductVersion
useplunk plunk < 0.8.0

Bug Bounty Relevance

59 / 100
✓ Network accessible
✓ Low complexity
✓ No user interaction

CVSS Score

4.3 / 10.0 v3.1
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

EPSS — Exploitation Probability

0.19%
Raw Score 0.001940
Percentile 9.1%
Date 2026-10-29

EPSS Trend

2026-10-29
0.00194
2026-10-28
0.00194

Intelligence Sources

nvd ref →