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CVE-2026-49252
critical
CVSS 9.9
Vulnerability in @deepstream/server (CVE-2026-49252)
Summary
vulnerability in @deepstream/server (CVE-2026-49252). Confidential information can be exposed externally. Exploitable via ``__proto__``. Mitigation: upgrade to `10.0.5` or later.
AI summary snake-internal / snake-material-v2
A vulnerability tracked as **CVE-2026-49252** has been found in @deepstream/server.
Attackers can target a specific entry point like ``__proto__`` over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 9.9/10.
What to do: upgrade @deepstream/server to **10.0.5** or later.
If unsure, ask your IT team or search "@deepstream/server CVE-2026-49252" on the vendor's site.
CVE-2026-49252 (@deepstream/server) — CWE-1321 / CVSS v3 9.9
Attack vector: remote (network-reachable) / no user interaction
Attack surface: `__proto__` / `constructor` / `prototype`
Patched: `10.0.5` — apply immediately
Workaround: Filter out all messages containing the path `__proto__`, `constructor`, `prototype`, **before they reach the server's message pipeline**
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.
❓ What is the problem
**A vulnerability** (CWE-1321) exists in @deepstream/server. Attackers reach the vulnerable code path via ``__proto__`` without authentication.
📍 Affected scope
@deepstream/server — . Attack surface: `__proto__` / `constructor` / `prototype`.
🔥 Severity
Severity: Critical (CVSS 9.9/10). Confidential information can be exposed externally
🔧 How to fix
Update to **10.0.5**.
🛡️ Workaround
Workaround: Filter out all messages containing the path `__proto__`, `constructor`, `prototype`, **before they reach the server's message pipeline**
🔍 Detection
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run `grep -r '@deepstream/server' .` against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response Actions (7 steps)
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
grep -r '@deepstream/server' . | 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 `@deepstream/server` を grep し、稼働しているサービス・バージョンを把握する。
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5Apply temporary workaround mitigate
Filter out all messages containing the path `__proto__`, `constructor`, `prototype`, **before they reach the server's message pipeline**パッチが適用されるまでの応急処置として、Filter out all messages containing the path `__proto__`, `constructor`, `prototype`, **before they reach the server's message pipeline** を実施。回避策の副作用 (機能低下) を確認した上で。
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6Apply patch patch
Upgrade @deepstream/server to 10.0.5ステージング環境で 10.0.5 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 3 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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7Post-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 Step 3 と同じログクエリでアラート再発が無いか継続監視。
Affected packages
npm
@deepstream/server
[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"10.0.5"}]}]
References
- advisory https://nvd.nist.gov/vuln/detail/CVE-2026-49252
- package https://github.com/deepstreamIO/deepstream.io
- web https://github.com/deepstreamIO/deepstream.io/commit/54b8e2958a98df444b5b5d9a66e22872afd84e44
- web https://github.com/deepstreamIO/deepstream.io/security/advisories/GHSA-9v98-6g37-x9g6
- web https://github.com/advisories/GHSA-9v98-6g37-x9g6