CVE-2023-26044 is a medium-severity (CVSS 5.3) Uncontrolled Resource Consumption vulnerability in react/http. A fix is available for react/http — see the affected versions and patch details below.
ReactPHP's HTTP server continues parsing unused multipart parts after reaching limits
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-2023-26044.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2023-26044 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,636 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
react/httpReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
Description
Summary
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.
Patches
The supplied patch resolves this vulnerability for ReactPHP.
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | react/http | ≥ 0.8.0&&< 1.9.0 | 1.9.0composer require react/http:^1.9.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for react/http, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update react/http to 1.9.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-26044 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.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2023-26044 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2023-26044. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2023-26044 in your dependencies?
O3 Security finds CVE-2023-26044 across Packagist dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.