CVE-2026-34486Known exploitationPublic exploitNetwork attack vector

Unauthenticated code execution via fail-open decryption

Published Apr 9, 2026 · Updated Apr 9, 2026

Code execution in Apache Tomcat 11.0.20, 10.1.53, and 9.0.116 allows remote attackers to execute commands via cluster traffic. EncryptInterceptor.messageReceived forwards raw channel bytes after decryption fails, allowing downstream Java deserialization of attacker-controlled data. Exploitation requires an enabled Cluster with EncryptInterceptor, network access to its receiver, and a usable deserialization gadget on the classpath.

CVSS severity7.5
High
EPSS probability98.62%
Next 30 days · Sep 16, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Code execution in Apache Tomcat 11.0.20, 10.1.53, and 9.0.116 allows remote attackers to execute commands via cluster traffic. EncryptInterceptor.messageReceived forwards raw channel bytes after decryption fails, allowing downstream Java deserialization of attacker-controlled data. Exploitation requires an enabled Cluster with EncryptInterceptor, network access to its receiver, and a usable deserialization gadget on the classpath.

The record

CVE
CVE-2026-34486
Published
Apr 9, 2026
Updated
Apr 9, 2026
Vendor
The Apache Software Foundation
Product
Apache Tomcat
Classifications
CWE-807, CWE-311, T1210
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 9, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 9, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=10.1.53
  2. Affected versionversion=11.0.20
  3. Affected versionversion=9.0.116

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Apache Software Foundation · Apache Tomcatversion=10.1.53; version=11.0.20; version=9.0.116

Published CVSS scores

7.5GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationReported
Public exploitPublished

Weakness, pattern, technique

CWE-807Reliance on Untrusted Inputs in a Security Decision
CWE-311Missing Encryption of Sensitive Data
T1210Exploitation of Remote Services

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Reported exploitation

Technologies

Your stack

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Your stack

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