CVE-2026-34483
HIGHCVE-2026-34483 is a high-severity (CVSS 7.5) CWE-116 vulnerability in org.apache.tomcat:tomcat-catalina. O3 Security confirms whether CVE-2026-34483 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Apache Tomcat: Incomplete escaping of JSON access logs
Blast Radius
org.apache.tomcat:tomcat-catalina☕org.apache.tomcat:tomcat-catalina☕org.apache.tomcat:tomcat-catalina☕org.apache.tomcat:tomcat☕org.apache.tomcat:tomcat☕org.apache.tomcat:tomcat☕org.apache.tomcat.embed:tomcat-embed-core☕org.apache.tomcat.embed:tomcat-embed-core+1 moreReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.
Description
Improper Encoding or Escaping of Output vulnerability in the JsonAccessLogValve component of Apache Tomcat.
This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.20, from 10.1.0-M1 through 10.1.53, from 9.0.40 through 9.0.116.
Users are recommended to upgrade to version 11.0.21, 10.1.54 or 9.0.117 , which fix the issue.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.apache.tomcat:tomcat-catalina | ≥ 9.0.40&&< 9.0.116 | 9.0.116 |
| ☕Maven | org.apache.tomcat:tomcat-catalina | ≥ 10.1.0-M1&&< 10.1.54 | 10.1.54 |
| ☕Maven | org.apache.tomcat:tomcat-catalina | ≥ 11.0.0-M1&&< 11.0.21 | 11.0.21 |
| ☕Maven | org.apache.tomcat:tomcat | ≥ 9.0.40&&< 9.0.116 | 9.0.116 |
| ☕Maven | org.apache.tomcat:tomcat | ≥ 10.1.0-M1&&< 10.1.54 | 10.1.54 |
| ☕Maven | org.apache.tomcat:tomcat | ≥ 11.0.0-M1&&< 11.0.21 | 11.0.21 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.apache.tomcat:tomcat-catalina. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update org.apache.tomcat:tomcat-catalina to 9.0.116 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-34483 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-34483 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-34483. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-34483 in your dependencies?
O3 detects CVE-2026-34483 across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.