Cross-user disclosure via cache directive whitespace bypass
Published Jun 17, 2026 · Updated Jun 17, 2026
Information disclosure in Node.js Undici allows remote attackers to read another caller's cached authenticated response. The cache interceptor preserves whitespace around qualified private or no-cache field names, so its literal authorization comparison fails and stores the response. Exploitation requires shared-cache mode, forwarded Authorization headers, a matching cache key, and an upstream response with a whitespace-padded directive.
Summary
What happened
Information disclosure in Node.js Undici allows remote attackers to read another caller's cached authenticated response. The cache interceptor preserves whitespace around qualified private or no-cache field names, so its literal authorization comparison fails and stores the response. Exploitation requires shared-cache mode, forwarded Authorization headers, a matching cache key, and an upstream response with a whitespace-padded directive.
The record
- CVE
- CVE-2026-9678
- Published
- Jun 17, 2026
- Updated
- Jun 17, 2026
- Vendor
- Node.js
- Product
- Undici
- Classifications
- CWE-524
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jun 17, 2026CVE publishedPublication date reported by the CVE source.
- Jun 17, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=7.0.0 <7.28.0
- Affected versionversion=8.0.0 <8.5.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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