{"id":"CVE-2026-84465","title":"Zammad is a web based open source helpdesk/customer support system","summary":"Zammad is a web based open source helpdesk/customer support system. Prior to 7.1.2, when Zammad checks the digital signature on an incoming S/MIME-signed email, it does not verify that the signing certificate is genuinely trusted, it onl…","severity":"high","cvss":7.1,"cvssVector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N","cwe":["CWE-290","CWE-295","CWE-347"],"vendor":"zammad","product":"zammad","affected":["zammad < 7.1.2"],"published":"2026-09-25","updated":"2026-09-25","sourceUpdated":"2026-09-25T19:17:58.123","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-84465","references":[{"url":"https://github.com/zammad/zammad/commit/9a07d0b8214ac4e8e10c23fce71d613bd0625524","label":"security-advisories@github.com"},{"url":"https://github.com/zammad/zammad/security/advisories/GHSA-m9ff-hjr3-93h4","label":"security-advisories@github.com"}],"tags":["nvd","cve.org"],"cvssSource":"cna","ingestedAt":"2026-09-25T19:15:39.030Z","slug":"CVE-2026-84465","body":"## Overview\n\nZammad is a web based open source helpdesk/customer support system. Prior to 7.1.2, when Zammad checks the digital signature on an incoming S/MIME-signed email, it does not verify that the signing certificate is genuinely trusted, it only checks whether a certificate with a matching name is already stored in the system. An attacker can create their own certificate using the name of a real, previously trusted sender and use it to send a forged email. Zammad will display that email with the same \"validly signed\" indicator as a genuine message from the real sender, even though the attacker never had access to that sender's actual certificate or private key. This issue is fixed in version 7.1.2.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":39,"depthScoreParts":{"impact":39.1,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}