CVE-2026-14643

Analyzed Analyzed - Analysis Complete

Cache Interceptor Mishandles Whitespace in Cache-Control Directives

Publication date: 2026-07-29

Last updated on: 2026-08-04

Assigner: openjs

Description

undici's cache interceptor mishandles optional whitespace placed around the equals sign of a qualified no-cache or private Cache-Control directive. In undici from 7.0.0 up to before 7.29.0 and from 8.0.0 up to before 8.9.0, the parser either drops the directive or stores a field name with literal quote characters, so the cache decision fails to recognize the qualification and the response is stored. In shared-cache mode, this lets a response containing one user's authenticated data be served from cache to a later caller, including an unauthenticated one, when both requests resolve to the same cache key. It affects applications that enable the cache interceptor in shared mode, forward Authorization headers upstream, and receive cacheable responses with qualified directives padded with whitespace around the equals sign. This is the whitespace-around-equals variant that the fix for CVE-2026-9678 did not normalize, and it is fixed in undici 7.29.0 and 8.9.0.

CVSS Scores

EPSS Scores

Probability:
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Meta Information

Published

2026-07-29

Last Modified

2026-08-04

Generated

2026-08-19

AI Q&A

2026-07-30

EPSS Evaluated

2026-08-18

NVD

CVE-2026-14643

EUVD

EUVD-2026-50567

Affected Vendors & Products

Vendor	Product	Version / Range
nodejs	undici	From 7.0.0 (inc) to 7.29.0 (exc)
nodejs	undici	From 8.0.0 (inc) to 8.9.0 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-436	Product A handles inputs or steps differently than Product B, which causes A to perform incorrect actions based on its perception of B's state.
CWE-524	The code uses a cache that contains sensitive information, but the cache can be read by an actor outside of the intended control sphere.

Attack-Flow Graph

Executive Summary

This vulnerability affects the undici library's cache interceptor. It mishandles optional whitespace around the equals sign in Cache-Control directives like no-cache or private. This causes the cache to either ignore the directive or store malformed field names, leading to improper caching behavior.

Detection Guidance

This vulnerability affects applications using undici's cache interceptor in shared mode with specific Cache-Control directives. Detection requires checking if your system uses undici versions between 7.0.0-7.28.0 or 8.0.0-8.8.0 and inspecting cache configurations for qualified no-cache or private directives with whitespace around equals signs.

Impact Analysis

In shared-cache mode, this flaw allows a cached response containing one user's authenticated data to be served to another user, including unauthenticated users. This happens when both requests share the same cache key due to the mishandled directive.

Compliance Impact

This vulnerability could lead to unauthorized access to sensitive user data, violating privacy regulations like GDPR and HIPAA. It risks exposing authenticated user information to unintended parties through improper caching.

Mitigation Strategies

Update undici to version 7.29.0 or 8.9.0 or later to address the cache interceptor issue. Disable the cache interceptor in shared mode if not required. Avoid forwarding Authorization headers upstream for cacheable responses with qualified Cache-Control directives.

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