HIGH

CVE-2025-53506

CVSS v3

7.5

HIGH

EPSS Score

2.1 %

exploit probability, as of 2026-10-18

CISA KEV

known exploited

Exploitation

—

SSVC status

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Affected and fixed versions

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

org.apache.tomcat:tomcat-coyoteMavenfrom 9.0.0.M1 · fixed in 9.0.107
org.apache.tomcat.embed:tomcat-embed-coreMavenfrom 11.0.0-M1 · fixed in 11.0.9
tomcatBitnamiall versions · fixed in 9.0.107
tomcatAlmaLinux:9all versions · fixed in 1:9.0.87-3.el9_6.3and 7 other packages
tomcatAlmaLinux:8all versions · fixed in 1:9.0.87-1.el8_10.6and 7 other packages
tomcat9AlmaLinux:10all versions · fixed in 1:9.0.87-5.el10_0.3and 7 other packages

Vendor advisories

CVE-2025-53506 Red Hat Product Security141 products fixed · 28 known affected
tomcat: Apache Tomcat denial of service
tomcat6 as a component of Red Hat Enterprise Linux 6 · tomcat6-admin-webapps as a component of Red Hat Enterprise Linux 6 · tomcat6-docs-webapp as a component of Red Hat Enterprise Linux 6
RHSA-2025:14180 Red Hat Product Security9 products fixed
Red Hat Security Advisory: tomcat security update
RHSA-2025:14181 Red Hat Product Security9 products fixed
Red Hat Security Advisory: tomcat security update
RHSA-2025:14183 Red Hat Product Security9 products fixed
Red Hat Security Advisory: tomcat security update
RHSA-2025:14177 Red Hat Product Security9 products fixed
Red Hat Security Advisory: tomcat security update
RHSA-2025:14182 Red Hat Product Security18 products fixed
Red Hat Security Advisory: tomcat security update

6 more advisories

Full record on 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.

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published: 2025-07-10
Last Modified: 2025-11-04

Frequently asked questions

What is CVE-2025-53506?

Is CVE-2025-53506 actively exploited?

Active exploitation of CVE-2025-53506 has not been confirmed. Its EPSS score was 2.1% on 2026-10-18, the estimated probability of exploitation in the next 30 days.

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

CVE-2025-53506 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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