Summary
ReactPHP's HTTP server continues parsing unused multipart parts after reaching input field and file upload limits
Previous versions of ReactPHP's HTTP server component contain a potential DoS vulnerability that can cause high CPU load when processing large HTTP request bodies. This vulnerability has little to no impact on the default configuration, but can be exploited when explicitly using the RequestBodyBufferMiddleware with very large settings. This might lead to consuming large amounts of CPU time for processing requests and significantly delay or slow down the processing of legitimate user requests.
Workarounds
Keeping the request body limit using
RequestBodyBufferMiddlewaresensible will mitigate it.Infrastructure or DevOps can place a reverse proxy in front of the ReactPHP HTTP server to filter out any excessive HTTP request bodies.
References
A similar vulnerability was discovered in PHP recently, see also PHP's security advisory (CVE-2023-0662). The fix is based on the PHP-FPM fix.
Impact
Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service. Typical impact: denial of service.
CVE-2023-26044 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 (1.9.0); 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.
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The supplied patch resolves this vulnerability for ReactPHP.
Frequently Asked Questions
- What is CVE-2023-26044? CVE-2023-26044 is a medium-severity uncontrolled resource consumption vulnerability in react/http (composer), affecting versions >= 0.8.0, < 1.9.0. It is fixed in 1.9.0. Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service.
- How severe is CVE-2023-26044? CVE-2023-26044 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 react/http are affected by CVE-2023-26044? react/http (composer) versions >= 0.8.0, < 1.9.0 is affected.
- Is there a fix for CVE-2023-26044? Yes. CVE-2023-26044 is fixed in 1.9.0. Upgrade to this version or later.
- Is CVE-2023-26044 exploitable, and should I be worried? Whether CVE-2023-26044 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-2023-26044 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-2023-26044? Upgrade
react/httpto 1.9.0 or later.