Vulnerability in vllm (CVE-2026-73557)
Summary
Vulnerability in vllm (CVE-2026-73557). Risk of unauthorized operations or information disclosure. Exploitable via POST /v1/chat/completions. Mitigation: upgrade to 0.26.0 or later.
Original description
The description as published by the source.
Executive Summary
The follow-up protection for CVE-2025-62164 is incomplete at vLLM revision 26587f9519e22a5c4549ead7595ad9ca3229c4fd. It wraps serialized prompt-embedding reconstruction and dense conversion in torch.sparse.check_sparse_tensor_invariants(), but PyTorch 2.11.0 implements that context with save/enable/restore operations over process-global state. Two prompt-embedding parts in one /v1/chat/completions request are gathered concurrently on the event loop's default executor. When one context exits before the other loads its tensor, it can restore the global flag to False while the second part remains inside its guard.
In a deterministic run against hash-verified source from the affected revision, the actual target loader rejected an invalid sparse payload as a negative control. The frozen chat tracker then scheduled benign and malicious parts on distinct asyncio_0 and asyncio_1 threads. The benign context exited, the malicious loader observed the invariant flag disabled, and torch.load(weights_only=True) reconstructed indices [[10], [10]] for a declared shape of [3, 3]. The run intercepted the target's to_dense() call before it operated on the invalid tensor.
This primary trigger requires --enable-prompt-embeds, which is default-off, but it does not require renderer_num_workers > 1, a multimodal model, or --enable-mm-embeds. API authentication is optional in the stock server: middleware is installed only when CLI or environment A…
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-2026-73557 has been found in vllm.
Attackers can target a specific entry point like POST /v1/chat/completions over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 5.3/10.
What to do: upgrade vllm to 0.26.0 or later.
If unsure, ask your IT team or search "vllm CVE-2026-73557" on the vendor's site.
CVE-2026-73557 (vllm) — CWE-362 / CVSS v3 5.3
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: POST /v1/chat/completions / False / asyncio_0 / asyncio_1
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-362) exists in vllm. Attackers reach the vulnerable code path via POST /v1/chat/completions without authentication.
Check the vendor advisory for the affected versions of vllm. Attack surface: POST /v1/chat/completions / False / asyncio_0 / asyncio_1.
Severity: Medium (CVSS 5.3/10). 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 POST /v1/chat/completions requests with malformed payloads or SQL meta-characters. 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。 -
2Hunt for indicators of compromise detect
grep 'POST /v1/chat/completions' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'アクセスログで
POST /v1/chat/completionsへの異常なリクエスト (不正な認証ヘッダ・SQLメタ文字)を過去 30〜90日分捜索。WAF/SIEM があれば該当パスのアラート発火履歴を確認。 -
3Apply 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と、Step 2 で見つけた異常検知の続報チェックを含めること。
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4Post-deployment verification verify
Replay attack against POST /v1/chat/completions on staging to confirm patch closes the vector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 Step 2 と同じログクエリでアラート再発が無いか継続監視。