How severe is CVE-2026-34579?

CVE-2026-34579 has a CVSS 4.0 base score of 5.3, rated medium severity.

Is CVE-2026-34579 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (28th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-34579?

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

Does CVE-2026-34579 have an EU (EUVD) identifier?

Yes. CVE-2026-34579 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-30996.

When was CVE-2026-34579 published?

CVE-2026-34579 was published on 2026-05-19 and last updated on 2026-06-17.

CVE-2026-34579

CVE-2026-34579 is a medium-severity vulnerability with a CVSS 4.0 base score of 5.3. 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-200.

Key facts

Severity: Medium (CVSS 4.0 base score 5.3)
EPSS exploit prediction: 0% (28th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-30996
Weakness: CWE-200
Published: 2026-05-19
Last modified: 2026-06-17

Description

Mantis Bug Tracker (MantisBT) is an open source issue tracker. Versions 2.28.1 and prior are vulnerable to Authorization Bypass through the private issue monitoring feature . Using a crafted POST request to bug_monitor_add.php, a user with project-level access can add themselves as a monitor for a private issue they do not have access to. Despite displaying an Access Denied error, the application accepts the request and creates a monitor relationship for the private issue. Direct access to the private issue remains blocked, but the user will receive email notifications for updates, leading to disclosure of the private issue's metadata and content. This issue has been fixed in version 2.28.2.

Frequently asked questions

What is CVE-2026-34579?: Mantis Bug Tracker (MantisBT) is an open source issue tracker. Versions 2.28.1 and prior are vulnerable to Authorization Bypass through the private issue monitoring feature . Using a crafted POST request to bug_monitor_add.php, a user with project-level access can add themselves as a monitor for a private issue they do not have access to. Despite displaying an Access Denied error, the application accepts the request and creates a monitor relationship for the private issue. Direct access to the private issue remains blocked, but the user will receive email notifications for updates, leading to disclosure of the private issue's metadata and content. This issue has been fixed in version 2.28.2.
How severe is CVE-2026-34579?: CVE-2026-34579 has a CVSS 4.0 base score of 5.3, rated medium severity.
Is CVE-2026-34579 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (28th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-34579?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-34579 have an EU (EUVD) identifier?: Yes. CVE-2026-34579 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-30996.
When was CVE-2026-34579 published?: CVE-2026-34579 was published on 2026-05-19 and last updated on 2026-06-17.

References

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