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.
Original description
The description as published by the source.
Nerdbank.MessagePack is a NativeAOT-compatible MessagePack serialization library. Prior to 1.1.62, Nerdbank.MessagePack contains an uncontrolled stack allocation vulnerability in DateTime decoding. A malicious MessagePack payload can declare an oversized timestamp extension length, causing the reader to allocate an attacker-controlled number of bytes on the stack. This can trigger a StackOverflowException, which is not catchable by user code and terminates the process. This vulnerability is fixed in 1.1.62.
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-2026-44375 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.
A vulnerability (CWE-789) exists in Nerdbank.MessagePack. Attackers reach the vulnerable code path via StackOverflowException without authentication.
Check the vendor advisory for the affected versions of Nerdbank.MessagePack. Attack surface: StackOverflowException / DateTime / tokenSize / stackalloc.
Severity: High (CVSS 7.5/10). Risk of unauthorized operations or information disclosure.
Update to 1.1.62.
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 'Nerdbank.MessagePack' . 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 '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。 -
2Apply 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を含めること。
-
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
- advisory github.com
- advisory nvd.nist.gov
- advisory github.com
- package github.com
- patch github.com
- patch github.com
- web github.com
- web github.com
- web github.com