How severe is CVE-2026-42498?

CVE-2026-42498 has a CVSS 3.x base score of 7.3, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.

Is CVE-2026-42498 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-42498?

CVE-2026-42498 affects Apache Tomcat. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-42498?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-42498 have an EU (EUVD) identifier?

Yes. CVE-2026-42498 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-29515.

When was CVE-2026-42498 published?

CVE-2026-42498 was published on 2026-05-12 and last updated on 2026-06-17.

CVE-2026-42498

CVE-2026-42498 is a high-severity vulnerability in Apache Tomcat with a CVSS 3.x base score of 7.3. 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: High (CVSS 3.x base score 7.3)
EPSS exploit prediction: 1% (42nd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-29515
Weakness: CWE-200
Affected product: Apache Tomcat
Published: 2026-05-12
Last modified: 2026-06-17

Description

Exposure of HTTP Authentication Header to unexpected hosts during WebSocket authentication vulnerability in Apache Tomcat. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.21, from 10.1.0-M1 through 10.1.54, from 9.0.2 through 9.0.117, from 8.5.24 through 8.5.100, from 7.0.83 through 7.0.109. Users are recommended to upgrade to version 11.0.22, 10.1.55 or 9.0.118, which fix the issue.

Frequently asked questions

What is CVE-2026-42498?: Exposure of HTTP Authentication Header to unexpected hosts during WebSocket authentication vulnerability in Apache Tomcat. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.21, from 10.1.0-M1 through 10.1.54, from 9.0.2 through 9.0.117, from 8.5.24 through 8.5.100, from 7.0.83 through 7.0.109. Users are recommended to upgrade to version 11.0.22, 10.1.55 or 9.0.118, which fix the issue.
How severe is CVE-2026-42498?: CVE-2026-42498 has a CVSS 3.x base score of 7.3, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.
Is CVE-2026-42498 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-42498?: CVE-2026-42498 affects Apache Tomcat. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-42498?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-42498 have an EU (EUVD) identifier?: Yes. CVE-2026-42498 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-29515.
When was CVE-2026-42498 published?: CVE-2026-42498 was published on 2026-05-12 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:apache:tomcat:*:*:*:*:*:*:*:*

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