CVE Catalog

CVE-2026-105752

LowCVSS 3.1
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.22%

11th percentile - higher than 11% of all known CVEs

Summary

vLLM is an inference and serving engine for large language models. Prior to 0.30.0, Harmony tool continuations submitted through POST /v1/responses requests rebuild the next-turn engine input without preserving the cache_salt value, placing the continuation prefix in the global unsalted cache namespace even when the caller enabled salting. On deployments with prefix caching enabled (default), an authenticated tenant who can reconstruct a victim's low-entropy post-tool history can submit the same continuation and use the cached_tokens_per_turn count to determine whether the prefix was previously processed, defeating tenant isolation.

Risk Assessment

An authenticated tenant can breach cache isolation and gain information about other tenants' prefix processing. This may lead to information leakage and confidentiality breaches in multi-tenant environments.

Recommendation

Update vLLM to version 0.30.0 or later, which fixes this issue. If updating is not possible, consider disabling prefix caching or restricting access to the /v1/responses endpoint.

Other vulnerabilities in vLLM

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Original NVD description (English source)

vLLM is an inference and serving engine for large language models. Prior to 0.30.0, Harmony tool continuations submitted through "POST /v1/responses" requests rebuild the next-turn engine input without preserving the cache_salt value, placing the continuation prefix in the global unsalted cache namespace even when the caller enabled salting. On deployments with prefix caching enabled, which is the default, an authenticated tenant who can reconstruct a victim's low-entropy post-tool history can submit the same continuation and use the cached_tokens_per_turn count to determine whether the prefix was previously processed, defeating the intended tenant isolation of salted prefix caching. This issue is fixed in version 0.30.0.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS