CVE-2026-85152

undici vulnerable to cross-origin cache poisoning via missing origin isolation in interceptors

Workarounds

Use a separate cache store and a separate interceptor instance for each origin, and do not share them across origins.

When interceptors.cache() or interceptors.deduplicate() is used with a dispatcher that does not carry a single authoritative origin, or when a request supplies its own origin, undici builds the cache and deduplication keys without the actual destination origin. If a cache store or interceptor instance is shared across more than one origin, otherwise-identical requests to different origins are keyed together.

An attacker who controls the response from one origin can then have that response returned for a request to a different, trusted origin when the method, path, and relevant headers match. This allows cross-origin information disclosure and persistent cache poisoning, including chains such as JWKS cache poisoning where a token signed with an attacker-held key is accepted as belonging to a trusted issuer.

Applications that share interceptors.cache() or interceptors.deduplicate() state across origins are affected. An Agent is not affected, because its dispatch options include the request origin.

This was introduced in undici 8.10.0 and affects 8.10.0 and 8.10.1.

CVE-2026-85152 has a CVSS score of 7.4 (High). 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 (8.10.2); upgrading removes the vulnerable code path.

Kodem intelligence

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1. What is CVE-2026-85152? CVE-2026-85152 is a high-severity security vulnerability in undici (npm), affecting versions >= 8.10.0, < 8.10.2. It is fixed in 8.10.2.
2. How severe is CVE-2026-85152? CVE-2026-85152 has a CVSS score of 7.4 (High). 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 undici are affected by CVE-2026-85152? undici (npm) versions >= 8.10.0, < 8.10.2 is affected.
4. Is there a fix for CVE-2026-85152? Yes. CVE-2026-85152 is fixed in 8.10.2. Upgrade to this version or later.
5. Is CVE-2026-85152 exploitable, and should I be worried? Whether CVE-2026-85152 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-2026-85152 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-2026-85152? Upgrade undici to 8.10.2 or later.

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