vLLM: Harmony tool continuations drop `cache_salt` — restoring a cross-tenant prefix-cache membership oracle

[ Description ]Official description

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.

[ Fixes ]Fixes and patches

• vllm 0.30.0Fixed version · GitHub Advisories · pip package vllm: upgrade to 0.30.0 or later (affected < 0.30.0)
• Patch on github.comVendor patch or bulletin · NVD · Reference tagged 'Patch' by NVD
• Patch on github.comVendor patch or bulletin · NVD · Reference tagged 'Patch' by NVD
• Patch on github.comVendor patch or bulletin · NVD · Reference tagged 'Patch' by NVD

[ Advisories ]Government CERT advisories

• BSI CERT-Bund23 Sep 2026WID-SEC-2026-3564

  vllm: Multiple vulnerabilities Translated from German

  CVE-2026-105757CVE-2026-105754CVE-2026-105755+1 more CVEs

[ Packages ]Affected open-source packages

• vllm pipAffected < 0.30.0 · fixed in 0.30.0 · GHSA-935w-9g4m-p28p

[ References ]References

• github.com/vllm-project/vllm/commit/6a2a2bb02b563b83f946012959fd3927984d072aPatch
• github.com/vllm-project/vllm/pull/50195Issue TrackingPatch
• github.com/vllm-project/vllm/pull/51818Issue TrackingPatch
• github.com/vllm-project/vllm/releases/tag/v0.30.0Release Notes
• github.com/vllm-project/vllm/security/advisories/GHSA-935w-9g4m-p28pMitigationVendor Advisory