Home/CVE/Uncontrolled Resource Consumption vulnerability in Apache Tomcat if an HTTP/2 client did not acknowledge the initial set
CVE

CVE-2025-53506

Uncontrolled Resource Consumption vulnerability in Apache Tomcat if an HTTP/2 client did not acknowledge the initial set

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.

HIGH · CVSS 7.5 EPSS 0.01247
Schedule remediation
  • SSVC automatable: yes - attacks can be scripted at scale
  • CVSS base score ≥ 7.0
Sigma rules1 YARA rules0
⬡

Weakness Classification

CWE-400Uncontrolled Resource Consumption
▤

Affected Products & Versions

3
apache tomcat>= 9.0.0 and <= 9.0.106
apache tomcat>= 10.1.0 and <= 10.1.42
apache tomcat>= 11.0.0 and <= 11.0.8
▤

Affected Packages

2
Language-ecosystem packages (from OSV) tied to this CVE, with the version that fixes it - the dependency-level detail NVD doesn’t carry.
Maven org.apache.tomcat.embed:tomcat-embed-core HIGH
Maven org.apache.tomcat:tomcat-coyote HIGH fixed in 11.0.9
◈

Sigma Hunt Rules

1
Exact rules name this CVE ID. Product rules name an affected product in their title. Related rules cover techniques used by actors who exploited this CVE. Showing the most relevant matches; the complete related set is on the full drill-down.
productmediumTomcat WebServer Logs Deleted
▣

Scoring & Timeline

7.5
HIGH · CVSS v3.1 · security@apache.org
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD10 Jul 2025 · 08:15 PM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
SSVC triage · cisa-vulnrichment
Exploitation
none
Automatable
yes
Technical impact
partial
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
⚑

Vendor Advisories

20
suse-csafSUSE-SU-2026:1058-1
suse-csafSUSE-SU-2025:03024-1
suse-csafSUSE-SU-2025:02978-1
suse-csafSUSE-SU-2025:02979-1
suse-csafopenSUSE-SU-2025:15440-1
🔗

References & Sources

3
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://lists.apache.org/thread/p09775q0rd185m6zz98krg0fp45j8kr0Issue TrackingMailing ListVendor Advisory
http://www.openwall.com/lists/oss-security/2025/07/10/13
https://lists.debian.org/debian-lts-announce/2025/07/msg00009.html
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