Apache Tomcat Missing Encryption of Sensitive Data
CVE-2026-34486 is a high-severity missing encryption of sensitive data 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: 11.0.20; 10.1.53; 9.0.116. The record does not name a fixed version, so check the vendor advisory. CISA added it to the Known Exploited Vulnerabilities catalogue on August 4, 2026, which means attacks have been observed in the wild.
Attackers are already exploiting this vulnerability, according to CISA.
What to do
- Check which version of Apache Tomcat you run against the affected versions below, and install the vendor's latest release.
- CISA's 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.
- Read the advisory on lists.apache.org for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
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
- HighAll data handled by the component can be read.
- Integrity
- NoneNothing can be modified.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N. Scored by CNA.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.5 | High | CISA (ADP) |
| CVSS 3.1 | 7.5 | High | CNA |
Official description
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.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Missing Encryption of Sensitive Data
The product does not encrypt sensitive or critical information before storage or transmission.
How developers prevent this class of flaw
- Clearly specify which data or resources are valuable enough that they should be protected by encryption. Require that any transmission or storage of this data/resource should use well-vetted encryption algorithms.
- Compartmentalize the system to have safe areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area. Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.
- When using industry-approved techniques, use them correctly. Don't cut corners by skipping resource-intensive steps (CWE-325). These steps are often essential for preventing common attacks.
More Missing Encryption of Sensitive Data vulnerabilities (CWE-311)
Timeline
- CVE record published.
- Added to CISA's Known Exploited Vulnerabilities catalogue.
- CISA published its SSVC assessment (exploitation: active, automatable: yes, technical impact: partial).
- Deadline for US federal agencies to remediate, set by CISA.
- Record last changed materially (score, affected products, status or references).
References
Advisories
Patches and release notes
- vicarius.io/vsociety/posts/cve-2026-34486-mitigation-script-rce-on-apache-tomcatMitigation, Third Party Advisory
Third-party and government advisories
- vicarius.io/vsociety/posts/cve-2026-34486-detection-script-rce-on-apache-tomcatThird Party Advisory
- access.redhat.com/errata/RHSA-2026:36787Third Party Advisory
- access.redhat.com/errata/RHSA-2026:36788Third Party Advisory
- access.redhat.com/errata/RHSA-2026:36789Third Party Advisory
- access.redhat.com/errata/RHSA-2026:36790Third Party Advisory
- access.redhat.com/errata/RHSA-2026:36876Third Party Advisory
- access.redhat.com/errata/RHSA-2026:36877Third Party Advisory
- access.redhat.com/errata/RHSA-2026:36878Third Party Advisory
- access.redhat.com/errata/RHSA-2026:36879Third Party Advisory
- access.redhat.com/errata/RHSA-2026:37136Third Party Advisory
- access.redhat.com/errata/RHSA-2026:37137Third Party Advisory
- access.redhat.com/errata/RHSA-2026:38505Third Party Advisory
- access.redhat.com/errata/RHSA-2026:39188Third Party Advisory
- access.redhat.com/errata/RHSA-2026:39189Third Party Advisory
- access.redhat.com/security/cve/CVE-2026-34486Third Party Advisory
Other vulnerabilities in Apache Tomcat
- 7.5 High severity
- 7.5 High severity
- 8.1 High severity
- 9.1 Critical severity
- 9.1 Critical severity
- 8.1 High severity
Recent Missing Encryption of Sensitive Data vulnerabilities
- 7.5 High severity
- 9.6 Critical severity
- 9.4 Critical severity
- 8.6 High severity
- 7.1 High severity
- 7.0 High severity
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