SCA: security update for s9y/serendipity (GHSA-458g-q4fh-mj6r)

high Tenable Self-Hosted Container Security Plugin ID 440357

Description

There are packages installed that are affected by a vulnerability referenced in the following CVE:

- Serendipity is a PHP-powered weblog engine. In versions 2.6-beta2 and below, the email sending
functionality in include/functions.inc.php inserts $_SERVER['HTTP_HOST'] directly into the Message-ID SMTP
header without validation, and the existing sanitization function serendipity_isResponseClean() is not
called on HTTP_HOST before embedding it. An attacker who can control the Host header during an email-
triggering action such as comment notifications or subscription emails can inject arbitrary SMTP headers
into outgoing emails. This enables identity spoofing, reply hijacking via manipulated Message-ID
threading, and email reputation abuse through the attacker's domain being embedded in legitimate mail
headers. This issue has been fixed in version 2.6.0. (CVE-2026-39971)

Solution

Update the s9y/serendipity library and its related packages to version 2.6.0 or later.

Plugin Details

Severity: High

ID: 440357

Version: Revision 1.6

Type: Local

Family: SCA Checks

Published: 4/15/2026

Updated: 7/2/2026

Supported Sensors: Tenable Cloud Security, Tenable Self-Hosted Container Security

Risk Information

VPR

Risk Factor: Low

Score: 2.3

Percentile: 9.42

Vendor

Vendor Severity: High

CVSS v2

Risk Factor: Medium

Base Score: 6.4

Temporal Score: 5

Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:N

CVSS Score Source: CVE-2026-39971

CVSS v3

Risk Factor: High

Base Score: 7.2

Temporal Score: 6.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N

Temporal Vector: CVSS:3.0/E:P/RL:O/RC:C

Vulnerability Information

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 4/14/2026

Vulnerability Publication Date: 4/14/2026

Reference Information

CVE: CVE-2026-39971

cwe: CWE-113

Detections

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