Is CVE-2025-53506 in the CISA KEV catalog?

No. CVE-2025-53506 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2025-53506?

CVE-2025-53506 has a CVSS v3 base score of 7.5 (HIGH).

What is the EPSS score for CVE-2025-53506?

CVE-2025-53506 has an EPSS score of 1.90% (77th percentile), estimating the probability of exploitation in the next 30 days.

CVE & CISA-KEV Catalog

CVE-2025-53506

HIGHEPSS 77th pctl

7.5

CVSS v3

NVD

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.

CWE-400Resource Exhaustion

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploit Intelligence

1.90%probability of exploitation in 30 days

77thpercentile

Elevated risk: more likely to be exploited than 77% of all known CVEs.

References

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-11-04.