CyberSecBulletin
CVE-2026-87022NVD status: Awaiting Analysis

Apache Tomcat: Improper Handling of Length Parameter Inconsistency

Published Updated By the CyberSecBulletin desk

CVE-2026-87022 is a high-severity improper handling of length parameter inconsistency vulnerability in Apache Tomcat from Apache, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected Apache Tomcat versions: 11.0.0-M1 through 11.0.25; 10.1.0-M1 through 10.1.59; 9.0.0.M1 through 9.0.121, and others listed below. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.54% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Check which version of Apache Tomcat you run against the affected versions below, and install the vendor's latest release.
  2. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
ApacheApache Tomcat11.0.0-M1 through 11.0.25; 10.1.0-M1 through 10.1.59; 9.0.0.M1 through 9.0.121; 8.5.0 through 8.5.100; 7.0.56 through 7.0.109Not stated

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
NoneNo data is disclosed.
Integrity
HighData or code can be modified at will.
Availability
NoneAvailability is not affected.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N. Scored by CISA (ADP).

Official description

Improper handling of length parameter inconsistency vulnerability in Apache Tomcat allows WebSocket message smuggling when per-message-deflate is used. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.25, from 10.1.0-M1 through 10.1.59, from 9.0.0.M1 through 9.0.121. The following versions were EOS at the time the CVE was created but are known to be affected: from 8.5.0 through 8.5.100, from 7.0.56 through 7.0.109. Other unsupported versions may also be affected. Users are recommended to upgrade to version 11.0.26, 10.1.60 or 9.1.22, which fix the issue.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Improper Handling of Length Parameter Inconsistency

The product parses a formatted message or structure, but it does not handle or incorrectly handles a length field that is inconsistent with the actual length of the associated data.

How developers prevent this class of flaw

  • When processing structured incoming data containing a size field followed by raw data, ensure that you identify and resolve any inconsistencies between the size field and the actual size of the data.
  • Do not let the user control the size of the buffer.
  • Validate that the length of the user-supplied data is consistent with the buffer size.

More Improper Handling of Length Parameter Inconsistency vulnerabilities (CWE-130)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).

References

Other vulnerabilities in Apache Tomcat

All Apache Tomcat vulnerabilities

Recent Improper Handling of Length Parameter Inconsistency vulnerabilities

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