CVE-2025-46570: vllm-project vllm Observable Timing Discrepancy
Vulnerability summary
CVE-2025-46570 is a low (CVSS 2.6) Observable Timing Discrepancy vulnerability in vllm-project vllm. EPSS estimates a 0.34% chance of exploitation in the next 30 days, higher than 25.5% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 0 · Related 3Timeline
- 29-05-2025PublishedVulnerability first disclosed.
- 29-05-2025Last modifiedVulnerability information updated.
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.
CVSS metrics
3 scores · 3 sources · 1 version- OSV · PypiEcosystem advisory · calculated2.6LowCVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:N/A:N
- NVDNIST2.6LowCVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:N/A:N
EPSS trend
Probability
0.34%
Chance of exploitation in the next 30 days
Percentile
26%
Versus all other CVEs
30-day change
+0.04 pp
From 0.29% on 20-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root cause- CWE-208Observable Timing DiscrepancyTwo separate operations in a product require different amounts of time to complete, in a way that is observable to an actor and reveals security-relevant information about the state of the product, such as whether a particular operation was successful or not.
- CWE-203Observable DiscrepancyThe product behaves differently or sends different responses under different circumstances in a way that is observable to an unauthorized actor.
Affected systems
PyPI1 product
- vllm< 77073c77bc2006eb80ea6d5128f076f5e6c6f54f | < 0.9.0
Vllm1 product
- vllm< 0.9.0
Vllm-project1 product
- vllm< 0.9.0
3 vendors · 3 products
References
6 links- github.com/vllm-project/vllm/security/advisories/GHSA-4qjh-9fv9-r85rX Refsource CONFIRMWEBAdvisoryVendor Advisory
- github.com/vllm-project/vllm/commit/77073c77bc2006eb80ea6d5128f076f5e6c6f54fX Refsource MISCWEBFIXPatch
- github.com/vllm-project/vllmPACKAGE