Vulnerability in vllm (CVE-2026-71486)
Summary
Vulnerability in vllm (CVE-2026-71486). Risk of unauthorized operations or information disclosure. Exploitable via GenerateResponse. Mitigation: upgrade to 0.26.0 or later.
Original description
The description as published by the source.
Summary
The /v1/completions/derender and /v1/chat/completions/derender endpoints accept caller-supplied GenerateResponse objects and postprocess every nested choices[*].token_ids list directly. Unlike the normal render/generate path, derender does not enforce model context length, resolved max_tokens, max_num_seqs, choice-count, or response-size bounds before detokenizing and returning the supplied token IDs. An authenticated API client can therefore make the CPU-only render frontend, or any server exposing these /v1 derender routes, spend CPU and memory proportional to attacker-chosen generated-output-shaped JSON rather than to a bounded generation result.
Technical Details
The render router registers /v1/chat/completions/derender and /v1/completions/derender in vllm/entrypoints/serve/render/api_router.py, and the OpenAI API server attaches this router whenever "generate" or "render" is in supported_tasks (vllm/entrypoints/openai/api_server.py). The routes are under /v1, so they are part of the OpenAI-compatible HTTP API surface and are protected by the API-key middleware when --api-key is configured.
The request types trust generated-output-shaped data from the client. In vllm/entrypoints/serve/disagg/protocol.py, GenerateResponseChoice accepts token_ids: list[int] | None = None, GenerateResponse accepts choices: list[GenerateResponseChoice], and DerenderCompletionRequest accepts `generate_responses: list[GenerateRespons…
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-71486 has been found in vllm.
Attackers can target a specific entry point like GenerateResponse over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 4.3/10.
What to do: upgrade vllm to 0.26.0 or later.
If unsure, ask your IT team or search "vllm CVE-2026-71486" on the vendor's site.
CVE-2026-71486 (vllm) — CWE-400 / CVSS v3 4.3
Attack vector: remote (network-reachable) / no user interaction
Attack surface: GenerateResponse / max_tokens / max_num_seqs / supported_tasks
Patched: 0.26.0 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-400) exists in vllm. Attackers reach the vulnerable code path via GenerateResponse.
Check the vendor advisory for the affected versions of vllm. Attack surface: GenerateResponse / max_tokens / max_num_seqs / supported_tasks.
Severity: Medium (CVSS 4.3/10). Risk of unauthorized operations or information disclosure.
Update to 0.26.0.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'vllm' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
grep -r 'vllm' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
vllmを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade vllm to 0.26.0ステージング環境で 0.26.0 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
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3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
References
- web github.com
- web github.com
- web github.com
- web github.com
- web nvd.nist.gov
- web github.com