← Vulnerability feed

Vulnerability record · CVE-2026-34718 · published 8 April 2026

CVE-2026-34718: Zammad vulnerability

Zammad · Zammad

Zammad is a web based open source helpdesk/customer support system. Prior to 7.0.1 and 6.5.4, the HTML sanitizer for ticket articles was missing proper sanitization of data: ... URI schemes, resulting in storing such malicious content in the database of the Zammad instance. The Zammad GUI is rendering this content, due to applied CSP rules no harm was done by e.g., clicking such a link. This vulnerability is fixed in 7.0.1 and 6.5.4.

5.3 CVSS 4.0 Medium EPSS 0.25% · top 84.9% CWE-80 · CWE-80
5.3CVSS 4.0 base score
0.25%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
1References
24 Jul 2026Last modified by NVD

Description

Zammad is a web based open source helpdesk/customer support system. Prior to 7.0.1 and 6.5.4, the HTML sanitizer for ticket articles was missing proper sanitization of data: ... URI schemes, resulting in storing such malicious content in the database of the Zammad instance. The Zammad GUI is rendering this content, due to applied CSP rules no harm was done by e.g., clicking such a link. This vulnerability is fixed in 7.0.1 and 6.5.4.

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/zammad/zammad/security/advisories/GHSA-c2cf-9fc7-jhf3 Vendor Advisory

Track CVE-2026-34718 inside VULONE

Watch it alongside the ransomware crews, C2 infrastructure and forum chatter that reference it, query it through the API and pull it into your SIEM over TAXII.

Start free Open in platform

Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.8CVE-2022-48021Zammad vulnerabilityA vulnerability in Zammad v5.3.0 allows attackers to execute arbitrary code or escalate privileges via a crafted message sent to the server.EPSS 0.88%9.8CVE-2022-35490Zammad improper restriction of authentication attempts vulnerabilityZammad 5.2.0 is vulnerable to privilege escalation. Zammad has a prevention against brute-force attacks trying to guess login credentials. After a co…EPSS 0.87%9.8CVE-2021-42090Zammad deserialization of untrusted data vulnerabilityAn issue was discovered in Zammad before 4.1.1. The Form functionality allows remote code execution because deserialization is mishandled.EPSS 2.3%9.8CVE-2021-42094Zammad command injection vulnerabilityAn issue was discovered in Zammad before 4.1.1. Command Injection can occur via custom Packages.EPSS 1.9%9.8CVE-2020-26030Zammad improper authentication vulnerabilityAn issue was discovered in Zammad before 3.4.1. There is an authentication bypass in the SSO endpoint via a crafted header, when SSO is not configure…EPSS 1.4%9.8CVE-2017-5619Zammad improper authentication vulnerabilityAn issue was discovered in Zammad before 1.0.4, 1.1.x before 1.1.3, and 1.2.x before 1.2.1. Attackers can login with the hashed password itself (e.g.…EPSS 1.5%9.8CVE-2017-6080Zammad cross-site request forgery vulnerabilityAn issue was discovered in Zammad before 1.0.4, 1.1.x before 1.1.3, and 1.2.x before 1.2.1, caused by lack of a protection mechanism involving HTTP A…EPSS 0.73%9.1CVE-2024-33668Zammad insecure direct object reference vulnerabilityAn issue was discovered in Zammad before 6.3.0. The Zammad Upload Cache uses insecure, partially guessable FormIDs to identify content. An attacker c…EPSS 0.45%

Source: NIST National Vulnerability Database (record CVE-2026-34718), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.