CVE-2026-29146Network attack vector

Cluster-message disclosure via default CBC padding oracle

Published Apr 9, 2026 · Updated Apr 9, 2026

Padding oracle in Apache Tomcat's EncryptInterceptor allows remote attackers to decrypt encrypted cluster messages over a network. The interceptor defaults to AES/CBC/PKCS5Padding, so attacker-modified ciphertext produces decryption outcomes that reveal padding validity. Exploitation requires network access to a cluster using EncryptInterceptor; successful attacks disclose cluster-message plaintext without altering it.

CVSS severity7.5
High
EPSS probability8.85%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Padding oracle in Apache Tomcat's EncryptInterceptor allows remote attackers to decrypt encrypted cluster messages over a network. The interceptor defaults to AES/CBC/PKCS5Padding, so attacker-modified ciphertext produces decryption outcomes that reveal padding validity. Exploitation requires network access to a cluster using EncryptInterceptor; successful attacks disclose cluster-message plaintext without altering it.

The record

CVE
CVE-2026-29146
Published
Apr 9, 2026
Updated
Apr 9, 2026
Vendor
The Apache Software Foundation
Product
Apache Tomcat
Classifications
CWE-642, CWE-209
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=10.0.0-M1 <=10.1.52
  2. Affected versionversion=11.0.0-M1 <=11.0.18
  3. Affected versionversion=7.0.100 <=7.0.109
  4. Affected versionversion=8.5.38 <=8.5.100
  5. Affected versionversion=9.0.13 <=9.0.115

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Apache Software Foundation · Apache Tomcatversion=10.0.0-M1 <=10.1.52; version=11.0.0-M1 <=11.0.18; version=7.0.100 <=7.0.109; version=8.5.38 <=8.5.100; version=9.0.13 <=9.0.115

Published CVSS scores

8.7GitHubCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
7.5CISA-ADPCVSS: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 exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-642External Control of Critical State Data
CWE-209Generation of Error Message Containing Sensitive Information

Public exploit references

No public exploit references are available in this record.

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

Technologies

Your stack

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Your stack

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