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CVE-2026-44375
high
CVSS 7.5
Vulnerability in Nerdbank.MessagePack (CVE-2026-44375)
Summary
vulnerability in Nerdbank.MessagePack (CVE-2026-44375). Risk of unauthorized operations or information disclosure. Exploitable via ``StackOverflowException``. Mitigation: upgrade to `1.1.62` or later.
AI summary snake-internal / snake-material-v2
A vulnerability tracked as **CVE-2026-44375** has been found in Nerdbank.MessagePack.
Attackers can target a specific entry point like ``StackOverflowException`` over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 7.5/10.
What to do: upgrade Nerdbank.MessagePack to **1.1.62** or later.
If unsure, ask your IT team or search "Nerdbank.MessagePack CVE-2026-44375" on the vendor's site.
CVE-2026-44375 (Nerdbank.MessagePack) — CWE-789 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: `StackOverflowException` / `DateTime` / `tokenSize` / `stackalloc`
Patched: `1.1.62` — 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.
❓ What is the problem
**A vulnerability** (CWE-789) exists in Nerdbank.MessagePack. Attackers reach the vulnerable code path via ``StackOverflowException`` without authentication.
📍 Affected scope
Nerdbank.MessagePack — . Attack surface: `StackOverflowException` / `DateTime` / `tokenSize` / `stackalloc`.
🔥 Severity
Severity: High (CVSS 7.5/10). Risk of unauthorized operations or information disclosure
🔧 How to fix
Update to **1.1.62**.
🛡️ Workaround
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
🔍 Detection
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run `grep -r 'Nerdbank.MessagePack' .` 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 'Nerdbank.MessagePack' . | 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 `Nerdbank.MessagePack` 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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6Apply patch patch
Upgrade Nerdbank.MessagePack to 1.1.62ステージング環境で 1.1.62 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
nuget
Nerdbank.MessagePack
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.1.62"}]}]
References
- advisory https://nvd.nist.gov/vuln/detail/CVE-2026-44375
- package https://github.com/AArnott/Nerdbank.MessagePack
- web https://github.com/AArnott/Nerdbank.MessagePack/commit/7d1eb319cfabe7280e70699946c9a48579fa2f30
- web https://github.com/AArnott/Nerdbank.MessagePack/pull/941
- web https://github.com/AArnott/Nerdbank.MessagePack/releases/tag/v1.1.62
- web https://github.com/AArnott/Nerdbank.MessagePack/security/advisories/GHSA-2cwq-pwfr-wcw3
- web https://github.com/msgpack/msgpack/blob/master/spec.md#timestamp-extension-type
- web https://github.com/advisories/GHSA-2cwq-pwfr-wcw3