Summary
undici vulnerable to cross-user information disclosure via whitespace around equals in Cache-Control directives
Workarounds
If upgrade is not immediately possible, disable shared-cache mode for traffic that includes Authorization headers, avoid caching responses to authenticated requests, or add Vary: Authorization upstream.
Impact
Undici's cache interceptor mishandles optional whitespace (OWS) placed around the = of a qualified no-cache or private Cache-Control directive, such as no-cache ="authorization" (OWS before =) or no-cache= "authorization" (OWS after =). The parser either drops the directive entirely or stores a field name with literal quote characters, so the downstream cache decisions do not recognize the qualification and the response is stored.
In shared-cache mode, this allows a response containing one user's authenticated data to be served from cache to a subsequent caller, including an unauthenticated caller, when both requests resolve to the same cache key. The impact class is identical to CVE-2026-9678 (GHSA-pr7r-676h-xcf6); this advisory covers the whitespace-around-= bypass that the earlier fix did not normalize.
Affected applications are those that explicitly enable the cache interceptor (interceptors.cache()) in shared mode, forward Authorization headers upstream, and receive cacheable responses with qualified private or no-cache directives whose field-name list is padded with OWS around the =.
CVE-2026-14643 has a CVSS score of 5.9 (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 (7.29.0, 8.9.0); 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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Upgrade to undici v7.29.0 or v8.9.0.
Frequently Asked Questions
- What is CVE-2026-14643? CVE-2026-14643 is a medium-severity security vulnerability in undici (npm), affecting versions >= 7.0.0, < 7.29.0. It is fixed in 7.29.0, 8.9.0.
- How severe is CVE-2026-14643? CVE-2026-14643 has a CVSS score of 5.9 (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 undici are affected by CVE-2026-14643? undici (npm) versions >= 7.0.0, < 7.29.0 is affected.
- Is there a fix for CVE-2026-14643? Yes. CVE-2026-14643 is fixed in 7.29.0, 8.9.0. Upgrade to this version or later.
- Is CVE-2026-14643 exploitable, and should I be worried? Whether CVE-2026-14643 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-2026-14643 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-2026-14643?
- Upgrade
undicito 7.29.0 or later - Upgrade
undicito 8.9.0 or later
- Upgrade