How severe is CVE-2026-34718?

CVE-2026-34718 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2026-34718 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (4th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-34718?

CVE-2026-34718 primarily affects Zammad. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-34718?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-34718 have an EU (EUVD) identifier?

Yes. CVE-2026-34718 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-20558.

When was CVE-2026-34718 published?

CVE-2026-34718 was published on 2026-04-08 and last updated on 2026-06-17.

CVE-2026-34718

CVE-2026-34718 is a medium-severity vulnerability in Zammad with a CVSS 3.x base score of 6.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-80.

Key facts

Severity: Medium (CVSS 3.x base score 6.1)
CVSS v4: 5.3
EPSS exploit prediction: 0% (4th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-20558
Weakness: CWE-80
Affected product: Zammad
Published: 2026-04-08
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2026-34718?: 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.
How severe is CVE-2026-34718?: CVE-2026-34718 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2026-34718 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (4th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-34718?: CVE-2026-34718 primarily affects Zammad. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-34718?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-34718 have an EU (EUVD) identifier?: Yes. CVE-2026-34718 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-20558.
When was CVE-2026-34718 published?: CVE-2026-34718 was published on 2026-04-08 and last updated on 2026-06-17.

References

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

Affected products (2)

cpe:2.3:a:zammad:zammad:*:*:*:*:*:*:*:*
cpe:2.3:a:zammad:zammad:7.0.0:*:*:*:*:*:*:*

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