CVE-2026-29129 is a high-severity (CVSS 7.5) Broken Cryptographic Algorithm vulnerability in org.apache.tomcat:tomcat-coyote. A fix is available for org.apache.tomcat:tomcat-coyote — see the affected versions and patch details below.
Apache Tomcat: TLS cipher order is not preserved
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-29129.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
org.apache.tomcat:tomcat-coyote☕org.apache.tomcat:tomcat-coyote☕org.apache.tomcat:tomcat-coyote☕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
Configured cipher preference order not preserved vulnerability in Apache Tomcat.
This issue affects Apache Tomcat: from 11.0.16 through 11.0.18, from 10.1.51 through 10.1.52, from 9.0.114 through 9.0.115.
Users are recommended to upgrade to version 11.0.20, 10.1.53 or 9.0.116, which fix the issue.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.apache.tomcat:tomcat-coyote | ≥ 9.0.114&&< 9.0.116 | 9.0.116org.apache.tomcat:tomcat-coyote:9.0.116 |
| ☕Maven | org.apache.tomcat:tomcat-coyote | ≥ 10.1.51&&< 10.1.53 | 10.1.53org.apache.tomcat:tomcat-coyote:10.1.53 |
| ☕Maven | org.apache.tomcat:tomcat-coyote | ≥ 11.0.16&&< 11.0.20 | 11.0.20org.apache.tomcat:tomcat-coyote:11.0.20 |
| ☕Maven | org.apache.tomcat:tomcat | ≥ 9.0.114&&< 9.0.116 | 9.0.116org.apache.tomcat:tomcat:9.0.116 |
| ☕Maven | org.apache.tomcat:tomcat | ≥ 10.1.51&&< 10.1.53 | 10.1.53org.apache.tomcat:tomcat:10.1.53 |
| ☕Maven | org.apache.tomcat:tomcat | ≥ 11.0.16&&< 11.0.20 | 11.0.20org.apache.tomcat:tomcat:11.0.20 |
Affected Products
tomcatapacheDetection & 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-coyote, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.apache.tomcat:tomcat-coyote to 9.0.116 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-29129 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.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Low impact. A flaw in Apache Tomcat allows the configured cipher preference order to be bypassed. This could lead to a server using a weaker cipher than intended, potentially reducing the security posture of TLS connections. This affects Red Hat Enterprise Linux systems running Apache Tomcat.
Configure Apache Tomcat to explicitly allow only strong cipher suites. This ensures that even if the preference order is not strictly honored, only secure ciphers are utilized for TLS connections. Edit the `server.xml` file, typically located at `/etc/tomcat/server.xml` or `/opt/tomcat/conf/server.xml`, and modify the `<Connector>` element to include a `ciphers` attribute listing only approved strong cipher suites. For example: `<Connector port="8443" protocol="org.apache.coyote.http11.Http11NioProtocol" SSLEnabled="true" scheme="https" secure="true" clientAuth="false" sslProtocol="TLSv1.2+TLSv1.3"…Source: Red Hat security advisory for CVE-2026-29129 (CC BY 4.0)
Frequently Asked Questions
Is CVE-2026-29129 in your dependencies?
Find it across Maven, including transitive dependencies.