7.5

CVE-2025-53506: Apache Tomcat: DoS via excessive h2 streams at connection start

Modified
AliasesUBUNTU-CVE-2025-53506DEBIAN-CVE-2025-53506CGA-2cqq-xxhv-cphq
Published 10-07-2025Last modified 04-11-2025

Vulnerability summary

CVE-2025-53506 is a high (CVSS 7.5) Uncontrolled Resource Consumption vulnerability in apache software foundation apache tomcat. EPSS estimates a 2.13% chance of exploitation in the next 30 days, higher than 81.9% of scored vulnerabilities.

Priority
Prioritisesevere

Severe, CVSS 7.5 (CVE.org); no exploitation reported by the 5 checked sources; EPSS 2% (FIRST, 03-11-2026)

Source freshness unavailable

How is this decided?
CVSS score
7.5/10
010
High · v3.1 (CVE.org)
EPSS score
2.13%
0%100%
Low · +0.09 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 21 · Related 10
DLA-4244-1DSA-6120-1DSA-6121-1MGASA-2025-0223OPENSUSE-SU-2025:15440-1OPENSUSE-SU-2025:15441-1

Timeline

  1. 10-07-2025
    PublishedVulnerability first disclosed.
  2. 04-11-2025
    Last modifiedVulnerability information updated.

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.

CVSS metrics

7 scores · 7 sources · 1 version

EPSS trend

Probability

2.13%

Chance of exploitation in the next 30 days

Percentile

82%

Versus all other CVEs

30-day change

Increase +0.09 pp

From 2.04% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

Chainguard9 products
  • tomcat-10.1< 10.1.43-r0
  • tomcat-10.1-openjdk-11< 10.1.43-r0
  • tomcat-10.1-openjdk-17< 10.1.43-r0
  • tomcat-10.1-openjdk-21< 10.1.43-r0
  • tomcat-11.0< 11.0.9-r0
Ubuntu4 products
  • tomcat10All versions (No fix recorded)
  • tomcat11All versions (No fix recorded)
  • tomcat8All versions (No fix recorded)
  • tomcat9All versions (No fix recorded)
Wolfi4 products
  • tomcat-11.0< 11.0.9-r0
  • tomcat-11.0-openjdk-17< 11.0.9-r0
  • tomcat-11.0-openjdk-21< 11.0.9-r0
  • tomcat-11.0-openjdk-25< 11.0.9-r0
Debian3 products
  • tomcat10< 10.1.52-1~deb12u1 | < 10.1.52-1~deb13u1 | < 10.1.46-1
  • tomcat11< 11.0.15-1~deb13u1 | < 11.0.11-1
  • tomcat9< 9.0.70-2
Apache1 product
  • tomcat≥ 9.0.0, ≤ 9.0.106 | ≥ 10.1.0, ≤ 10.1.42 | ≥ 11.0.0, ≤ 11.0.8
Apache software foundation1 product
  • apache tomcat≥ 11.0.0-M1, ≤ 11.0.8 | ≥ 10.1.0-M1, ≤ 10.1.42 | ≥ 9.0.0.M1, ≤ 9.0.106 | ≥ 8.5.0, ≤ 8.5.100
Org.apache.tomcat1 product
  • tomcat-coyote≥ 11.0.0-M1, < 11.0.9 | ≥ 10.1.0-M1, < 10.1.43 | ≥ 9.0.0.M1, < 9.0.107 | ≥ 8.5.0, ≤ 8.5.100
Org.apache.tomcat.embed1 product
  • tomcat-embed-core≥ 8.5.0, ≤ 8.5.100 | ≥ 9.0.0.M1, < 9.0.107 | ≥ 10.1.0-M1, < 10.1.43 | ≥ 11.0.0-M1, < 11.0.9

8 vendors · 24 products

References

12 links
Show all 12 references