Summary
Workarounds
There is no workaround, except using a custom HaProxyMessageDecoder.
References
When parsing a TLV with type = PP2_TYPE_SSL, the value can be again a TLV with type = PP2_TYPE_SSL and so on.
The only limitation of the recursion is that the TLV length cannot be bigger than 0xffff because it is encoded in an unsigned short type.
Providing a TLV with a nesting level that is large enough will lead to raising of a StackOverflowError.
The StackOverflowError will be caught if HAProxyMessageDecoder is used as part of Netty’s ChannelPipeline, but using it directly without the ChannelPipeline will lead to a thrown exception / crash.
For more information
If you have any questions or comments about this advisory:
- Open an issue in netty
Impact
A StackOverflowError can be raised when parsing a malformed crafted message due to an infinite recursion.
CVE-2022-41881 has a CVSS score of 5.3 (Medium). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (4.1.86.Final); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Remediation advice
Users should upgrade to 4.1.86.Final.
Frequently Asked Questions
- What is CVE-2022-41881? CVE-2022-41881 is a medium-severity security vulnerability in io.netty:netty-codec-haproxy (maven), affecting versions < 4.1.86.Final. It is fixed in 4.1.86.Final.
- How severe is CVE-2022-41881? CVE-2022-41881 has a CVSS score of 5.3 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of io.netty:netty-codec-haproxy are affected by CVE-2022-41881? io.netty:netty-codec-haproxy (maven) versions < 4.1.86.Final is affected.
- Is there a fix for CVE-2022-41881? Yes. CVE-2022-41881 is fixed in 4.1.86.Final. Upgrade to this version or later.
- Is CVE-2022-41881 exploitable, and should I be worried? Whether CVE-2022-41881 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2022-41881 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2022-41881? Upgrade
io.netty:netty-codec-haproxyto 4.1.86.Final or later.