vLLM tool continuations drop cache_salt to restore prefix-cache oracle

# vLLM tool continuations drop cache_salt to restore prefix-cache oracle

https://gcdradar.vercel.app/incidents/vllm-tool-continuations-drop-cache-salt-to-restore-prefix-ca · AIR-2026-0239 · closed 2026-10-05

- Lane: Patch now
- Severity: 2 (Disclosed vulnerability)
- Fix status: Fix status unknown
- First reported: 2026-10-05
- AI role: Attack on AI
- Products: vLLM
- CVE ids: CVE-2026-105752
- CVSS: 3.1

## Summary

Tool continuations in vLLM fail to preserve cache_salt values, placing continuation prefixes in the global unsalted namespace. This allows authenticated tenants to determine prefix-cache membership of other users' histories.

## What to do

No action recorded; read the sources below and the vendor's advisory.

## Latest updates

- 2026-10-06: CVE-2026-105752: vLLM: Harmony tool continuations drop `cache_salt` — restoring a cross-tenant prefix-cache membership oracle (https://github.com/advisories/GHSA-935w-9g4m-p28p)
- 2026-10-05: CVE-2026-105752: vLLM is an inference and serving engine for large language models. (https://nvd.nist.gov/vuln/detail/CVE-2026-105752)

## Sources

- 2026-10-05 NVD: CVE-2026-105752: vLLM is an inference and serving engine for large language models. https://nvd.nist.gov/vuln/detail/CVE-2026-105752
- 2026-10-06 GitHub Advisory Database: CVE-2026-105752: vLLM: Harmony tool continuations drop `cache_salt` — restoring a cross-tenant prefix-cache membership oracle https://github.com/advisories/GHSA-935w-9g4m-p28p

Verify against the vendor's advisory before changing production. Data CC BY-SA 4.0, https://gcdradar.vercel.app.