CVE-2026-33732

A pathname parsing discrepancy in srvx's FastURL allows middleware bypass on the Node.js adapter when a raw HTTP request uses an absolute URI with a non-standard scheme (e.g. file://).

Details

When Node.js receives an absolute URI in the request line (e.g. GET file://hehe?/internal/run HTTP/1.1), req.url is set verbatim to file://hehe?/internal/run. Since this doesn't start with /, NodeRequestURL passes it directly to FastURL as a string, which stores it in #href for lazy manual parsing.

FastURL#getPos() locates the pathname by finding :// then scanning for the next /, but this fails for URLs like file://hehe?/internal/run where a ? appears before the first / after the authority. The manual parser extracts pathname as /internal/run, while native URL correctly parses it as pathname / with search ?/internal/run.

This discrepancy means the router (using the fast-path) matches /internal/run, but if any middleware triggers a deopt to native URL (e.g. by accessing hostname), subsequent middleware sees a different pathname, bypassing route-based middleware guards.

This is a bypass of CVE-2026-33131.

Route-based middleware (auth guards, rate limiters, etc.) can be bypassed on the Node.js adapter when a prior middleware triggers FastURL deopt. Requires sending a raw HTTP request (not possible from browsers).

CVE-2026-33732 has a CVSS score of 4.8 (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 (0.11.13); upgrading removes the vulnerable code path.

Kodem intelligence

srvx FastURL constructor now deopts to native URL for any string not starting with /, ensuring consistent pathname resolution.

1. What is CVE-2026-33732? CVE-2026-33732 is a medium-severity security vulnerability in srvx (npm), affecting versions < 0.11.13. It is fixed in 0.11.13.
2. How severe is CVE-2026-33732? CVE-2026-33732 has a CVSS score of 4.8 (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.
3. Which versions of srvx are affected by CVE-2026-33732? srvx (npm) versions < 0.11.13 is affected.
4. Is there a fix for CVE-2026-33732? Yes. CVE-2026-33732 is fixed in 0.11.13. Upgrade to this version or later.
5. Is CVE-2026-33732 exploitable, and should I be worried? Whether CVE-2026-33732 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
6. What actually determines whether CVE-2026-33732 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.
7. How do I fix CVE-2026-33732? Upgrade srvx to 0.11.13 or later.