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CVE-2026-44497
critical
CVSS 9.1
Vulnerability in zfnd (CVE-2026-44497)
Summary
vulnerability in zfnd (CVE-2026-44497). Data can be tampered with by attackers. Exploitable via ``zcashd``. Mitigation: upgrade to `4.4.0` or later.
AI summary openai / gpt-4o
Zebra is software for managing Zcash nodes, and an issue in its older versions can improperly handle certain transaction forms, risking network partition. This can lead to transaction stoppages or fraudulent transactions. It's fixed in the latest versions; therefore, prompt software updates are recommended.
In older versions of ZEBRA, the mishandling of invalid hash types during sighash computation leads to a potential consensus split. The issue is addressed by updating to zebrad 4.4.0 and zebra-script 6.0.0, where the buffer is filled with random bytes on validation failure to force the expected signature validation failure.
❓ What is the problem
Insufficient error handling of invalid sighash type in Zcash node software Zebra.
📍 Affected scope
During sighash computation in older versions of ZEBRA prior to zebrad 4.4.0 and zebra-script 6.0.0.
🔥 Severity
Critical, allowing network partitioning and potential double-spend attacks.
🔧 How to fix
Upgrade to zebrad version 4.4.0 and zebra-script version 6.0.0.
🛡️ Workaround
No existing workarounds; immediate upgrade is required.
🔍 Detection
Monitor consensus splits between Zebra and zcashd nodes.
Related past incidents Similar incidents extracted from past CVEs
CVE-2026-41583
Initial fix that introduced insufficient error handling, leading to the separate issue in CVE-2026-44497.
Similar in theme to handling errors that can lead to unintended exposures.
If this happens at your company Expected impact per business scenario
📌 ブロックチェーン金融システムにおける場合
取引が停止し、二重支払いのリスクが高まる可能性があります。
📌 暗号通貨取引所での採用
ネットワークの分断によって顧客資産の安全性が脅かされ、信頼が損なわれる可能性があります。
📌 ZcashのマイナーがZebraを使用する場合
コンセンサス分裂により不正確なブロック承認が発生する可能性があります。
Recommended action
zebradとzebra-scriptのクライアントを直ちにアップデートすることが重要です。
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 'zfnd' . | 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 `zfnd` 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 zfnd to 4.4.0ステージング環境で 4.4.0 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 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。
References
- patch [email protected]