How severe is CVE-2025-53506?

CVE-2025-53506 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 none, integrity none, and availability high.

Is CVE-2025-53506 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (77th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-53506?

CVE-2025-53506 affects Apache Tomcat. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-53506?

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-2025-53506 have an EU (EUVD) identifier?

Yes. CVE-2025-53506 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-21032.

When was CVE-2025-53506 published?

CVE-2025-53506 was published on 2025-07-10 and last updated on 2026-06-17.

CVE-2025-53506

CVE-2025-53506 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-400.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 2% (77th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-21032
Weakness: CWE-400
Affected product: Apache Tomcat
Published: 2025-07-10
Last modified: 2026-06-17

Description

Uncontrolled Resource Consumption vulnerability in Apache Tomcat if an HTTP/2 client did not acknowledge the initial settings frame that reduces the maximum permitted concurrent streams. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.8, from 10.1.0-M1 through 10.1.42, from 9.0.0.M1 through 9.0.106. The following versions were EOL at the time the CVE was created but are known to be affected: 8.5.0 through 8.5.100. Other EOL versions may also be affected. Users are recommended to upgrade to version 11.0.9, 10.1.43 or 9.0.107, which fix the issue.

Frequently asked questions

What is CVE-2025-53506?: Uncontrolled Resource Consumption vulnerability in Apache Tomcat if an HTTP/2 client did not acknowledge the initial settings frame that reduces the maximum permitted concurrent streams. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.8, from 10.1.0-M1 through 10.1.42, from 9.0.0.M1 through 9.0.106. The following versions were EOL at the time the CVE was created but are known to be affected: 8.5.0 through 8.5.100. Other EOL versions may also be affected. Users are recommended to upgrade to version 11.0.9, 10.1.43 or 9.0.107, which fix the issue.
How severe is CVE-2025-53506?: CVE-2025-53506 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 none, integrity none, and availability high.
Is CVE-2025-53506 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (77th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-53506?: CVE-2025-53506 affects Apache Tomcat. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-53506?: 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-2025-53506 have an EU (EUVD) identifier?: Yes. CVE-2025-53506 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-21032.
When was CVE-2025-53506 published?: CVE-2025-53506 was published on 2025-07-10 and last updated on 2026-06-17.

References

Affected products (1)

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

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