undici up to 7.30.1/8.12.3 Cache Interceptor escape output

Summaryinfo

A vulnerability has been found in undici up to 7.30.1/8.12.3 and classified as problematic. Affected by this vulnerability is an unknown functionality of the component Cache Interceptor. Performing a manipulation results in escape output. This vulnerability is known as CVE-2026-120222. Remote exploitation of the attack is possible. No exploit is available. The affected component should be upgraded.

Detailsinfo

A vulnerability, which was classified as problematic, was found in undici up to 7.30.1/8.12.3. This affects an unknown part of the component Cache Interceptor. The manipulation with an unknown input leads to a escape output vulnerability. CWE is classifying the issue as CWE-116. The product prepares a structured message for communication with another component, but encoding or escaping of the data is either missing or done incorrectly. As a result, the intended structure of the message is not preserved. This is going to have an impact on availability. The summary by CVE is:

undici is an HTTP client for Node.js. In versions 7.0.0 through 7.30.1 and 8.0.0 through 8.12.3, when the cache interceptor is composed with a downstream handler that throws during response processing (such as the built-in dump interceptor exceeding its maxSize, or the decompress interceptor rejecting more than five Content-Encoding values), a throw raised asynchronously while a cached response is replayed escapes as an uncaught exception or unhandled promise rejection and terminates the Node.js process. A malicious or compromised HTTP server can crash any such client by serving a cacheable response that triggers the throw on replay, including on a 304 revalidation of a stale entry, so the impact is availability only. The issue is fixed in undici 7.30.2 and 8.12.4, and users should upgrade to one of those versions or later. As a workaround, avoid composing the cache interceptor with a response handler that throws during response processing until upgrading.

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2026-120222 since 10/31/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Neither technical details nor an exploit are publicly available.

Upgrading to version 7.30.2 or 8.12.4 eliminates this vulnerability.

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Productinfo

Name

• undici

Version

• 7.30.0
• 7.30.1
• 8.12.0
• 8.12.1
• 8.12.2
• 8.12.3

CPE 2.3info

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CPE 2.2info

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