CkbApplication · Nervos
CVE-2021-45698
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 · uneditedAn issue was discovered in the ckb crate before 0.40.0 for Rust. A get_block_template RPC call may fail in situations where it is supposed to select a Nervos CKB blockchain transaction with a higher fee rate than another transaction.
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 · moderate confidenceThe ckb crate before version 0.40.0 contains a logic flaw in the get_block_template RPC call that causes incorrect transaction selection based on fee rates. The bug prevents proper selection of Nervos CKB blockchain transactions with higher fee rates when multiple candidates exist, potentially leading to suboptimal block template generation and economic inefficiency in fee market operations.
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
CkbApplication
< 0.40.0CVSS 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
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
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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Identify installed ckb versionRun 'ckb --version' or check the running ckb process version to determine if it is below 0.40.0Affected if The version returned is less than 0.40.0
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Confirm get_block_template RPC is exposedCheck the ckb RPC configuration file or running service for the get_block_template endpoint availability. This is typically exposed via the RPC service port (default 8114)Affected if The get_block_template RPC method is accessible and the ckb version is below 0.40.0
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Inspect RPC service configurationExamine the ckb configuration (ckb.toml or similar) for RPC module settings that enable the get_block_template handlerAffected if The RPC configuration enables the tx_pool module containing get_block_template and the version is below 0.40.0
If the ckb instance is version 0.40.0 or higher, the environment is not affected by this CVE.
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.
dbcve · scoped0.40.0
Upgrade the ckb Rust crate to version 0.40.0 or later to obtain the fixed transaction fee rate comparison logic in the get_block_template RPC handler.
ckb 0.40.0
- Update the ckb crate dependency in your Cargo.toml to version 0.40.0 or later
- Run cargo update to fetch the updated dependency
- Run cargo build to recompile your project with the fixed version
- Test the get_block_template RPC call to verify the transaction selection works correctly
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Ckb
Scoped from the published advisory
- Consultation2.0 h
- Implementation1.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,224.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-45698 — 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-2021-45698 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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