CVE-2026-9678
Description
A flaw was found in Undici. The cache interceptor in shared-cache mode incorrectly classifies certain responses as cacheable due to improper handling of whitespace-padded Cache-Control header field names. This vulnerability allows an unauthenticated attacker to access authenticated user data from the cache, leading to information disclosure. This occurs when both authenticated and unauthenticated requests resolve to the same cache key.
Statement
This Moderate information disclosure flaw in Undici's cache interceptor, when configured in shared-cache mode, allows an unauthenticated attacker to retrieve sensitive authenticated user data. This is due to incorrect parsing of Cache-Control headers containing whitespace-padded field names, leading to cached responses being served improperly. Red Hat products are affected if they explicitly enable shared-cache mode, forward Authorization headers, and process non-canonical Cache-Control directives.
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.9 | N/A | 5.9 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | High | N/A | High |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | High | N/A | High |
| Integrity Impact | None | N/A | None |
| Availability Impact | None | N/A | None |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
cve.org: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Understanding the Weakness (CWE)
Other
Technical Impact: Varies by Context
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