Summary
s2n-tls has undefined behavior at process exit
Workarounds
The atexit handler may be disabled by calling s2n_disable_atexit() prior to initializing s2n-tls. The atexit handler is off by default in the patched versions. For further details, refer to s2n-tls Usage Guide: Initialization and Teardown.
If you have any questions or comments about this advisory, we ask that you contact AWS/Amazon Security via our vulnerability reporting page [2] or directly via email to [email protected]. Please do not create a public GitHub issue.
[1] https://github.com/aws/s2n-tls/releases/tag/v1.5.9
[2] Vulnerability reporting page: https://aws.amazon.com/security/vulnerability-reporting
Impact
s2n-tls uses the Linux atexit function to register functions that clean up the global state when the process exits. In multi-threaded environments, the atexit handler may clean up state which is still in use by other threads. When this occurs, the exiting process may experience a segmentation fault or other undefined behavior.
Customers of AWS services do not need to take action. Applications using s2n-tls should upgrade to the most recent release of s2n-tls.
Impacted versions: < v1.5.9.
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.
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The patch commit 493b771 is included in s2n-tls v1.5.9 [1]
Frequently Asked Questions
- What is GHSA-RP9H-RF7G-HWGR? GHSA-RP9H-RF7G-HWGR is a low-severity security vulnerability in s2n-tls (rust), affecting versions < 0.3.7. It is fixed in 0.3.7.
- Which versions of s2n-tls are affected by GHSA-RP9H-RF7G-HWGR? s2n-tls (rust) versions < 0.3.7 is affected.
- Is there a fix for GHSA-RP9H-RF7G-HWGR? Yes. GHSA-RP9H-RF7G-HWGR is fixed in 0.3.7. Upgrade to this version or later.
- Is GHSA-RP9H-RF7G-HWGR exploitable, and should I be worried? Whether GHSA-RP9H-RF7G-HWGR 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 GHSA-RP9H-RF7G-HWGR 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 GHSA-RP9H-RF7G-HWGR? Upgrade
s2n-tlsto 0.3.7 or later.