How severe is CVE-2026-34483?

CVE-2026-34483 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2026-34483 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (37th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-34483?

CVE-2026-34483 affects Apache Tomcat. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-34483?

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-2026-34483 have an EU (EUVD) identifier?

Yes. CVE-2026-34483 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-21053.

When was CVE-2026-34483 published?

CVE-2026-34483 was published on 2026-04-09 and last updated on 2026-06-17.

CVE-2026-34483

CVE-2026-34483 is a high-severity vulnerability in Apache Tomcat with a CVSS 3.x base score of 7.5. 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-116.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 0% (37th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-21053
Weakness: CWE-116
Affected product: Apache Tomcat
Published: 2026-04-09
Last modified: 2026-06-17

Description

Improper Encoding or Escaping of Output vulnerability in the JsonAccessLogValve component of Apache Tomcat. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.20, from 10.1.0-M1 through 10.1.53, from 9.0.40 through 9.0.116. Users are recommended to upgrade to version 11.0.21, 10.1.54 or 9.0.117 , which fix the issue.

Frequently asked questions

What is CVE-2026-34483?: Improper Encoding or Escaping of Output vulnerability in the JsonAccessLogValve component of Apache Tomcat. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.20, from 10.1.0-M1 through 10.1.53, from 9.0.40 through 9.0.116. Users are recommended to upgrade to version 11.0.21, 10.1.54 or 9.0.117 , which fix the issue.
How severe is CVE-2026-34483?: CVE-2026-34483 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2026-34483 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (37th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-34483?: CVE-2026-34483 affects Apache Tomcat. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-34483?: 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-2026-34483 have an EU (EUVD) identifier?: Yes. CVE-2026-34483 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-21053.
When was CVE-2026-34483 published?: CVE-2026-34483 was published on 2026-04-09 and last updated on 2026-06-17.

References

Affected products (1)

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

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