CVE-2025-46570

vLLM’s Chunk-Based Prefix Caching Vulnerable to Potential Timing Side-Channel

LOW
2.6
CVSS Score
Published: May 29, 2025 at 04:32 PM UTC
Updated: June 17, 2026 at 09:26 AM UTC
1 product affected across 1 vendorvLLM

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Severity
LOW2.6
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

Description

vLLM is an inference and serving engine for large language models (LLMs). Prior to version 0.9.0, when a new prompt is processed, if the PageAttention mechanism finds a matching prefix chunk, the prefill process speeds up, which is reflected in the TTFT (Time to First Token). These timing differences caused by matching chunks are significant enough to be recognized and exploited. This issue has been patched in version 0.9.0.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 0.9.0
Affected range stops below 0.9.0, so it looks safe — our inference, not a vendor statement

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

2.6LOWGitHub_M
Attack Vector
NETWORK
Complexity
HIGH
Privileges
LOW
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
LOW
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusANALYZED
CWE
CWE-208CWE-203

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