{"resultsPerPage":1,"startIndex":0,"totalResults":1,"format":"NVD_CVE","version":"2.0","timestamp":"2026-05-07T19:39:41.498","vulnerabilities":[{"cve":{"id":"CVE-2026-39971","sourceIdentifier":"security-advisories@github.com","published":"2026-04-15T04:17:39.763","lastModified":"2026-04-23T13:59:19.810","vulnStatus":"Analyzed","cveTags":[],"descriptions":[{"lang":"en","value":"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."}],"metrics":{"cvssMetricV31":[{"source":"security-advisories@github.com","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N","baseScore":7.2,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"CHANGED","confidentialityImpact":"LOW","integrityImpact":"LOW","availabilityImpact":"NONE"},"exploitabilityScore":3.9,"impactScore":2.7}]},"weaknesses":[{"source":"security-advisories@github.com","type":"Primary","description":[{"lang":"en","value":"CWE-113"}]}],"configurations":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:s9y:serendipity:*:*:*:*:*:*:*:*","versionEndExcluding":"2.6.0","matchCriteriaId":"25355E06-ECC8-4A6C-ADB1-1A8ED17E5ABF"},{"vulnerable":true,"criteria":"cpe:2.3:a:s9y:serendipity:2.6.0:beta1:*:*:*:*:*:*","matchCriteriaId":"D31C5F34-5B83-4955-870B-0D1AC375DA24"}]}]}],"references":[{"url":"https://github.com/s9y/Serendipity/releases/tag/2.6.0","source":"security-advisories@github.com","tags":["Patch"]},{"url":"https://github.com/s9y/Serendipity/security/advisories/GHSA-458g-q4fh-mj6r","source":"security-advisories@github.com","tags":["Exploit","Vendor Advisory","Mitigation"]}]}}]}