CVE-2026-39971
- Source
- https://cve.org/CVERecord?id=CVE-2026-39971
- Import Source
- https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-39971.json
- JSON Data
- https://api.osv.dev/v1/vulns/CVE-2026-39971
- Aliases
- Published
- 2026-04-14T23:35:49Z
- Modified
- 2026-08-12T03:51:45Z
- Severity
-
- 7.2 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N CVSS Calculator
- Summary
- Serendipity: Host Header Injection leads to SMTP header injection via unvalidated HTTP_HOST
- Details
-
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.
- Database specific
{ "cna_assigner": "GitHub_M", "cwe_ids": [ "CWE-113" ], "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/39xxx/CVE-2026-39971.json" }- References
Affected packages
Git / github.com/s9y/serendipity
Affected ranges
- Type
- GIT
- Repo
- https://github.com/s9y/serendipity
- Events
-
Introduced0 Unknown introduced commit / All previous commits are affectedFixed
- Database specific
-
Show details
{ "cpe": "cpe:2.3:a:s9y:serendipity:*:*:*:*:*:*:*:*", "extracted_events": [ { "introduced": "0" }, { "fixed": "2.6.0" } ], "source": [ "AFFECTED_FIELD", "CPE_RANGE", "REFERENCES" ] }