CVE-2020-14199
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedBIP-143 in the Bitcoin protocol specification mishandles the signing of a Segwit transaction, which allows attackers to trick a user into making two signatures in certain cases, potentially leading to a huge transaction fee. NOTE: this affects all hardware wallets. It was fixed in 1.9.1 for the Trezor One and 2.3.1 for the Trezor Model T.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceBIP-143 (Bitcoin Improvement Proposal 143), which defines the signature hashing algorithm for Segregated Witness transactions, contains an implementation flaw that allows tricking a user into authorizing two separate signatures for a single transaction. This can be exploited to redirect funds through an abnormally high transaction fee, effectively stealing funds from the victim.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data< 2.3.1< 1.9.1CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Check Trezor Model T firmware versionConnect your Trezor Model T device to a computer, open the Trezor Wallet interface at wallet.trezor.io, navigate to Device Settings, and locate the firmware version displayed thereAffected if The displayed firmware version is lower than 2.3.1 (for example, 2.3.0, 2.2.x, or earlier)
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Check Trezor One firmware versionConnect your Trezor One device to a computer, open the Trezor Wallet interface at wallet.trezor.io, navigate to Device Settings, and locate the firmware version displayed thereAffected if The displayed firmware version is lower than 1.9.1 (for example, 1.9.0, 1.8.x, or earlier)
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Verify BIP-143 signature behavior (advanced)If you must sign a SegWit transaction, manually verify that only one signature is being authorized for the transaction by reviewing the transaction details on the device screen before confirming. Check that the displayed transaction fee matches your intended amountAffected if The device appears to authorize two separate signatures for what should be a single transaction, or if the transaction fee displayed is unexpectedly high
You are affected if your Trezor Model T runs firmware below 2.3.1 or your Trezor One runs firmware below 1.9.1, and you sign SegWit transactions using BIP-143.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor data1.9.12.3.1
Hardware wallet manufacturers must update their firmware to version 1.9.1 (Trezor One) or 2.3.1 (Trezor Model T) or later, which contain the corrected BIP-143 implementation that prevents the double-signature vulnerability.
- Consultation4.0 h
- Implementation12.0 h
- Testing8.0 h
- Review / QA4.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-14199 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2020-14199 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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