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CVE-2020-26243
Buffer Overflow in nanopb (CVE-2020-26243)
Summary
vulnerability in nanopb (CVE-2020-26243). Risk of unauthorized operations or information disclosure. Exploitable via ``no_unions``. Mitigation: upgrade to `0.4.4` or later.
AI summary snake-internal / snake-material-v2
A vulnerability tracked as **CVE-2020-26243** has been found in nanopb.
Attackers can target a specific entry point like ``no_unions`` over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: ?/10.
What to do: upgrade nanopb to **0.4.4** or later.
If unsure, ask your IT team or search "nanopb CVE-2020-26243" on the vendor's site.
CVE-2020-26243 (nanopb) — CWE-119 /
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: `no_unions` / `FT_POINTER`
Patched: `0.4.4` — 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-119) exists in nanopb. Attackers reach the vulnerable code path via ``no_unions`` without authentication.
📍 Affected scope
nanopb — . Attack surface: `no_unions` / `FT_POINTER`.
🔥 Severity
Severity: ?. Risk of unauthorized operations or information disclosure
🔧 How to fix
Update to **0.4.4**.
🛡️ 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 'nanopb' .` 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 'nanopb' . | 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 `nanopb` 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 nanopb to 0.4.4ステージング環境で 0.4.4 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
PyPI
nanopb
[{"type":"ECOSYSTEM","events":[{"introduced":"0.4.0"},{"fixed":"0.4.4"}]}]
References
- advisory https://github.com/nanopb/nanopb/security/advisories/GHSA-85rr-4rh9-hhwh
- advisory https://nvd.nist.gov/vuln/detail/CVE-2020-26243
- advisory https://github.com/nanopb/nanopb/blob/2b48a361786dfb1f63d229840217a93aae064667/CHANGELOG.txt
- advisory https://github.com/advisories/GHSA-85rr-4rh9-hhwh
- package https://pypi.org/project/nanopb
- patch https://github.com/nanopb/nanopb/issues/615
- patch https://github.com/nanopb/nanopb/commit/4fe23595732b6f1254cfc11a9b8d6da900b55b0c