CVE-2026-29129
Cipher Preference Order Vulnerability in Apache Tomcat SSL/TLS
Publication date: 2026-04-09
Last updated on: 2026-04-14
Assigner: Apache Software Foundation
Description
Description
CVSS Scores
EPSS Scores
| Probability: | |
| Percentile: |
Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| apache | tomcat | From 10.1.51 (inc) to 10.1.53 (exc) |
| apache | tomcat | From 11.0.16 (inc) to 11.0.20 (exc) |
| apache | tomcat | From 9.0.114 (inc) to 9.0.116 (exc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-327 | The product uses a broken or risky cryptographic algorithm or protocol. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability in Apache Tomcat involves the configured cipher preference order not being preserved. This means that the order in which cryptographic ciphers are preferred or prioritized by the server may not be maintained as intended.
How can this vulnerability impact me? :
If the cipher preference order is not preserved, it could lead to weaker or less secure ciphers being used during encrypted communications. This may reduce the overall security of data transmitted between clients and the server, potentially exposing sensitive information to interception or attacks.
What immediate steps should I take to mitigate this vulnerability?
To mitigate this vulnerability, users are recommended to upgrade Apache Tomcat to versions 11.0.20, 10.1.53, or 9.0.116, which contain the fix for the issue.
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
The vulnerability involves the TLS cipher preference order not being preserved as configured, which could allow weaker ciphers to be selected despite administrator settings.
This could potentially weaken the security of TLS connections, which may impact compliance with security requirements in standards and regulations such as GDPR and HIPAA that mandate strong encryption practices to protect sensitive data.
However, the provided information does not explicitly state the direct impact on compliance with these standards.
How can this vulnerability be detected on my network or system? Can you suggest some commands?
This vulnerability involves the TLS cipher preference order not being preserved as configured in affected Apache Tomcat versions. Detection would involve verifying the TLS cipher order behavior on your Tomcat server.
One approach is to check the Apache Tomcat version to see if it falls within the vulnerable ranges: 11.0.16 through 11.0.18, 10.1.51 through 10.1.52, or 9.0.114 through 9.0.115.
To detect the vulnerability on your system, you can:
- Check the Tomcat version by running: `catalina.sh version` or checking the server logs.
- Test the TLS cipher preference order by using tools such as `openssl s_client` or `nmap` with the `--script ssl-enum-ciphers` option to observe which ciphers are negotiated.
- Example command to test TLS ciphers with OpenSSL: `openssl s_client -connect yourserver:443 -cipher <cipher_list>` to see which cipher is accepted.
- Use `nmap --script ssl-enum-ciphers -p 443 yourserver` to enumerate supported ciphers and their order.
If the cipher preference order does not match your configured preference, and your Tomcat version is vulnerable, the system is affected.