How severe is CVE-2026-40598?

CVE-2026-40598 has a CVSS 4.0 base score of 6.9, rated medium severity.

Is CVE-2026-40598 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (36th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-40598?

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

Does CVE-2026-40598 have an EU (EUVD) identifier?

Yes. CVE-2026-40598 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-31494.

When was CVE-2026-40598 published?

CVE-2026-40598 was published on 2026-05-22 and last updated on 2026-06-17.

CVE-2026-40598

CVE-2026-40598 is a medium-severity vulnerability with a CVSS 4.0 base score of 6.9. 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-79.

Key facts

Severity: Medium (CVSS 4.0 base score 6.9)
EPSS exploit prediction: 0% (36th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-31494
Weakness: CWE-79
Published: 2026-05-22
Last modified: 2026-06-17

Description

Mantis Bug Tracker (MantisBT) is an open source issue tracker. In versions 2.28.1 and below, improper escaping of the redirection page (retrieved from the request's Referer header) allows an attacker to inject HTML. While this is generally not directly actionable as modern browsers will URL-encode special characters, on some specific server configurations this could poison the cache, leading to cross-site scripting. This issue has been fixed in version 2.28.2.

Frequently asked questions

What is CVE-2026-40598?: Mantis Bug Tracker (MantisBT) is an open source issue tracker. In versions 2.28.1 and below, improper escaping of the redirection page (retrieved from the request's Referer header) allows an attacker to inject HTML. While this is generally not directly actionable as modern browsers will URL-encode special characters, on some specific server configurations this could poison the cache, leading to cross-site scripting. This issue has been fixed in version 2.28.2.
How severe is CVE-2026-40598?: CVE-2026-40598 has a CVSS 4.0 base score of 6.9, rated medium severity.
Is CVE-2026-40598 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (36th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-40598?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-40598 have an EU (EUVD) identifier?: Yes. CVE-2026-40598 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-31494.
When was CVE-2026-40598 published?: CVE-2026-40598 was published on 2026-05-22 and last updated on 2026-06-17.

References

Other CWE-79 (Cross-site Scripting (XSS)) vulnerabilities

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CVE-2024-6886 — Critical (CVSS 10.0): Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting') vulnerability in Gitea…
CVE-2023-45144 — Critical (CVSS 10.0): com.xwiki.identity-oauth:identity-oauth-ui is a package to aid in building identity and service providers based on…
CVE-2023-45138 — Critical (CVSS 10.0): Change Request is an pplication allowing users to request changes on a wiki without publishing the changes directly.…
CVE-2022-4361 — Critical (CVSS 10.0): Keycloak, an open-source identity and access management solution, has a cross-site scripting (XSS) vulnerability in the…

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