API key recovery via variable-time bearer comparison
Published Oct 7, 2025 · Updated Oct 7, 2025
Covert timing channel in vLLM before 0.11.0rc2 allows remote attackers to recover an API key through repeated bearer-token requests. AuthenticationMiddleware directly compares the supplied Authorization value with configured bearer tokens, producing longer checks as more leading characters match. Exploitation requires the built-in API-key option and enough network samples to distinguish timing differences; a recovered key grants access to protected API endpoints.
Summary
What happened
Covert timing channel in vLLM before 0.11.0rc2 allows remote attackers to recover an API key through repeated bearer-token requests. AuthenticationMiddleware directly compares the supplied Authorization value with configured bearer tokens, producing longer checks as more leading characters match. Exploitation requires the built-in API-key option and enough network samples to distinguish timing differences; a recovered key grants access to protected API endpoints.
The record
- CVE
- CVE-2025-59425
- Published
- Oct 7, 2025
- Updated
- Oct 7, 2025
- Vendor
- vLLM Project
- Product
- vLLM
- Classifications
- CWE-385, T1110.001
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Oct 7, 2025CVE publishedPublication date reported by the CVE source.
- Oct 7, 2025Record 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=< 0.11.0rc2
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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Public exploit references
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Technologies
Your stack
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Your stack
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