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Security Digest · Vulnerability record · Known exploited

CVE-2026-34486: Apache Tomcat Missing Encryption of Sensitive Data Vulnerability

Exploited in the wild (CISA KEV). Missing Encryption of Sensitive Data vulnerability in Apache Tomcat due to the fix for CVE-2026-29146 allowing the bypass of the EncryptInterceptor.

CISA KEV · added 2026-08-04 CVSS 7.5 High EPSS 6.6% · p94 Check exposure

Updated By erroneo.us Security Desk25 references Seen in the digest for Aug 4, 2026

Should you act?

Exploited: patch now if you run it

CISA has confirmed exploitation in the wild. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

  • Yes, if you run Apache Tomcat. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2026-08-04, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2026-08-07; treat that as the outer limit, not the target.
  • EPSS 6.6%, percentile 94: FIRST’s model estimates a 6.6% chance of exploitation activity in the next 30 days, higher than 94% of all scored CVEs (elevated). EPSS is a probability, not a verdict.
  • Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
  • Editorial verdict: Check exposure. Tomcat CVE-2026-34486: Cluster EncryptInterceptor Bypass — Exploited, but only against three specific Tomcat releases running session-replication clustering with the EncryptInterceptor and a reachable cluster port; check those three things today, and most Tomcat users will find they are not exposed.

What it is

Missing Encryption of Sensitive Data vulnerability in Apache Tomcat due to the fix for CVE-2026-29146 allowing the bypass of the EncryptInterceptor. This issue affects Apache Tomcat: 11.0.20, 10.1.53, 9.0.116. Users are recommended to upgrade to version 11.0.21, 10.1.54 or 9.0.117, which fix the issue.

CISA’s summary

Apache Tomcat contains a missing encryption of sensitive data vulnerability that allows the bypass of the EncryptInterceptor. This vulnerability can be chained with CVE‑2025‑24813.

Weakness type: CWE-311, CWE-807.

Product: Apache Tomcat · Assigned by: apache · Published: 2026-04-09

Affected and fixed versions

VendorProductAffected versions (per CVE record)
Apache Software FoundationApache Tomcat11.0.20, 10.1.53, 9.0.116

Severity scores

Scored byCVSSScoreVector
CISA-ADP3.17.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
redhat-SADP3.17.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
  • Attack vector: network (remotely reachable)
  • Attack complexity: low
  • Privileges required: none (no login)
  • User interaction: none
  • Scope: unchanged

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

  • CISA KEV: added 2026-08-04; federal due date 2026-08-07. Known ransomware use: Unknown.
  • CISA required action: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
  • CISA SSVC assessment: exploitation active, automatable yes, technical impact partial.
  • FIRST EPSS (model of 2026-10-21): 6.56% probability of exploitation activity in the next 30 days; percentile 94.

Timeline

  • — CVE record published by apache
  • — erroneo.us brief: Tomcat CVE-2026-34486: Cluster EncryptInterceptor Bypass
  • — Added to CISA’s Known Exploited Vulnerabilities catalog
  • — CISA remediation deadline for US federal agencies
  • — CVE record last updated

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vendor and project advisories, patches

  1. lists.apache.org lists.apache.org
  2. access.redhat.com access.redhat.com
  3. access.redhat.com access.redhat.com
  4. access.redhat.com access.redhat.com
  5. access.redhat.com access.redhat.com
  6. access.redhat.com access.redhat.com
  7. access.redhat.com access.redhat.com
  8. access.redhat.com access.redhat.com
  9. access.redhat.com access.redhat.com
  10. access.redhat.com access.redhat.com
  11. access.redhat.com access.redhat.com
  12. access.redhat.com access.redhat.com
  13. access.redhat.com access.redhat.com
  14. access.redhat.com access.redhat.com

Vulnerability records

  1. CVE.org record CVE-2026-34486 cve.org
  2. NVD entry CVE-2026-34486 nvd.nist.gov

Government

  1. CISA Known Exploited Vulnerabilities catalog entry cisa.gov
  2. Listed in CISA KEV notes (cisa.gov) cisa.gov
  3. Listed in CISA KEV notes (cisa.gov) cisa.gov

Other references from the CVE record and advisory

  1. socradar.io socradar.io
  2. vicarius.io vicarius.io
  3. vicarius.io vicarius.io
  4. access.redhat.com access.redhat.com
  5. RHBZ#2457027 bugzilla.redhat.com
  6. security.access.redhat.com security.access.redhat.com

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