CVE-2026-34721: Zammad is a web based open source helpdesk/customer support system

Q: How do I fix CVE-2026-34721?

zammad: upgrade to 6.5.4. Exact commands for each OS are on this page.

Q: Is CVE-2026-34721 being exploited?

CVE-2026-34721 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-34721 affect?

CVE-2026-34721 affects zammad. Severity is medium (CVSS 6.5). Zammad is a web based open source helpdesk/customer support system. Prior to 7.0.1 and 6.5.4, the OAuth callback endpoints for Microsoft, Google, and Facebook external credentials do not validate a CSRF state parameter. This vulnerability i

Q: How urgent is CVE-2026-34721?

Priority 23/100. No elevated risk signals yet.

Routine

MEDIUM 6.5UPGRADE

CVE-2026-34721 is a medium-severity flaw (CVSS 6.5) affecting zammad. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Zammad is a web based open source helpdesk/customer support system. Prior to 7.0.1 and 6.5.4, the OAuth callback endpoints for Microsoft, Google, and Facebook external credentials do not validate a CSRF state parameter. This vulnerability is fixed in 7.0.1 and 6.5.4.

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.1% (top 99%)
CISA exploited list	No
Weakness	CWE-352
Published	2026-04-08
Last modified	2026-07-24

Publisher (CNA): GitHub, Inc. · Vendor: zammad

Last updated 2026-07-24 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-08 19:25 UTCPublished CVE record published
2026-07-24 22:10 UTCUpdated Record last modified

zammad zammad UPGRADE

Affected: < 6.5.4 · 7.0.0

Fixed in: 6.5.4

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy zammad || rpm -q zammad || zammad --version

2. UPGRADE to 6.5.4 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade zammad

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade zammad

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-34721?

zammad: upgrade to 6.5.4. Exact commands for each OS are on this page.

Is CVE-2026-34721 being exploited?

CVE-2026-34721 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-34721 affect?

CVE-2026-34721 affects zammad. Severity is medium (CVSS 6.5). Zammad is a web based open source helpdesk/customer support system. Prior to 7.0.1 and 6.5.4, the OAuth callback endpoints for Microsoft, Google, and Facebook external credentials do not validate a CSRF state parameter. This vulnerability i

How urgent is CVE-2026-34721?

Priority 23/100. No elevated risk signals yet.

Related CVEs

CVE-2026-102489 CRITICAL 9.8 EXPLOITED UPGRADE Zammad GmbH Zammad Session Fixation Vulnerability
CVE-2026-102490 HIGH 7.8 EXPLOITED UPGRADE Zammad GmbH Zammad Improper Privilege Management Vulnerability
CVE-2026-34723 HIGH 7.5 UPGRADE Zammad is a web based open source helpdesk/customer support system
CVE-2026-34724 HIGH 7.2 DOWNGRADE Zammad is a web based open source helpdesk/customer support system
CVE-2026-34248 MEDIUM 5.7 DOWNGRADE Zammad is a web based open source helpdesk/customer support system

References

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