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.
Fix
Patch, vendor advisory and mitigation references on NVD 4
- https://github.com/vllm-project/vllm/commit/6a2a2bb02b563b83f946012959fd3927984d072a Patch
- https://github.com/vllm-project/vllm/pull/50195 Issue Tracking, Patch
- https://github.com/vllm-project/vllm/pull/51818 Issue Tracking, Patch
- https://github.com/vllm-project/vllm/security/advisories/GHSA-935w-9g4m-p28p Mitigation, Vendor Advisory
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 1
- First seenCVSS 3.1 · vllmNVD modified 2026-10-08 01:29
Affected (CPE criteria) 1
cpe:2.3:a:vllm:vllm:*:*:*:*:*:*:*:*
References 5
- https://github.com/vllm-project/vllm/commit/6a2a2bb02b563b83f946012959fd3927984d072a Patch
- https://github.com/vllm-project/vllm/pull/50195 Issue Tracking, Patch
- https://github.com/vllm-project/vllm/pull/51818 Issue Tracking, Patch
- https://github.com/vllm-project/vllm/releases/tag/v0.30.0 Release Notes
- https://github.com/vllm-project/vllm/security/advisories/GHSA-935w-9g4m-p28p Mitigation, Vendor Advisory