CVE-2026-34483: CWE-116 Improper Encoding or Escaping of Output in Apache Software Foundation Apache Tomcat
An improper encoding or escaping of output vulnerability exists in the JsonAccessLogValve component of Apache Tomcat. This affects multiple versions across Tomcat 9.0, 10.1, and 11.0 branches. The vulnerability allows for potential exposure of sensitive data due to improper handling of output encoding. Fixed versions have been released to address this issue.
AI Analysis
Technical Summary
This vulnerability (CVE-2026-34483) in Apache Tomcat arises from improper encoding or escaping of output in the JsonAccessLogValve component, classified under CWE-116. It affects multiple Apache Tomcat versions across the 9.x, 10.x, and 11.x branches. The improper output encoding could potentially expose sensitive data or cause other security issues related to output handling. The Apache Software Foundation has released fixed versions (11.0.21, 10.1.54, and 9.0.117) that resolve this vulnerability. No cloud service is involved, and no known active exploits have been reported.
Potential Impact
The vulnerability allows for improper encoding or escaping of output in the JsonAccessLogValve, which can lead to exposure of sensitive information (confidentiality impact is high). There is no impact on integrity or availability reported. The CVSS score of 7.5 reflects a high severity due to the potential confidentiality impact and the fact that the vulnerability is remotely exploitable without privileges or user interaction.
Mitigation Recommendations
A fix is available. Users should upgrade Apache Tomcat to versions 11.0.21, 10.1.54, or 9.0.117 to remediate this vulnerability. No additional mitigation steps are indicated beyond applying the official updates.
CVE-2026-34483: CWE-116 Improper Encoding or Escaping of Output in Apache Software Foundation Apache Tomcat
Description
An improper encoding or escaping of output vulnerability exists in the JsonAccessLogValve component of Apache Tomcat. This affects multiple versions across Tomcat 9.0, 10.1, and 11.0 branches. The vulnerability allows for potential exposure of sensitive data due to improper handling of output encoding. Fixed versions have been released to address this issue.
CVSS v3.1
Score 7.5high
Affected software
pkg:maven/org.apache.tomcat/tomcatRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability (CVE-2026-34483) in Apache Tomcat arises from improper encoding or escaping of output in the JsonAccessLogValve component, classified under CWE-116. It affects multiple Apache Tomcat versions across the 9.x, 10.x, and 11.x branches. The improper output encoding could potentially expose sensitive data or cause other security issues related to output handling. The Apache Software Foundation has released fixed versions (11.0.21, 10.1.54, and 9.0.117) that resolve this vulnerability. No cloud service is involved, and no known active exploits have been reported.
Potential Impact
The vulnerability allows for improper encoding or escaping of output in the JsonAccessLogValve, which can lead to exposure of sensitive information (confidentiality impact is high). There is no impact on integrity or availability reported. The CVSS score of 7.5 reflects a high severity due to the potential confidentiality impact and the fact that the vulnerability is remotely exploitable without privileges or user interaction.
Mitigation Recommendations
A fix is available. Users should upgrade Apache Tomcat to versions 11.0.21, 10.1.54, or 9.0.117 to remediate this vulnerability. No additional mitigation steps are indicated beyond applying the official updates.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- apache
- Date Reserved
- 2026-03-30T07:40:44.705Z
- Cvss Version
- null
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 69d806d21cc7ad14da15a55c
Added to database: 04/09/2026, 20:06:42 UTC
Last enriched: 04/17/2026, 12:17:03 UTC
Last updated: 07/31/2026, 19:22:58 UTC
Views: 374
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.