CVE-2021-45698: An issue was discovered in the ckb crate before 0.40.0 for Rust

Q: How do I fix CVE-2021-45698?

ckb: upgrade to 0.40.0. Exact commands for each OS are on this page.

Q: Is CVE-2021-45698 being exploited?

CVE-2021-45698 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2021-45698 affect?

CVE-2021-45698 affects ckb. Severity is critical (CVSS 9.8). An 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.

Q: How urgent is CVE-2021-45698?

Priority 57/100. Critical severity; Remotely exploitable, no login, no user action

This month

CRITICAL 9.8REMOTEUPGRADE

CVE-2021-45698 is a critical-severity flaw (CVSS 9.8) affecting ckb. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An 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.

Why this priority

Critical severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.2% (top 31%)
CISA exploited list	No
Published	2021-12-27
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: nervos

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2021-12-27 00:15 UTCPublished CVE record published
2026-06-17 04:13 UTCUpdated Record last modified

nervos ckb UPGRADE

Affected: < 0.40.0

Fixed in: 0.40.0

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy ckb || rpm -q ckb || ckb --version

2. UPGRADE to 0.40.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade ckb

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade ckb

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-45698?

ckb: upgrade to 0.40.0. Exact commands for each OS are on this page.

Is CVE-2021-45698 being exploited?

CVE-2021-45698 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-45698 affect?

CVE-2021-45698 affects ckb. Severity is critical (CVSS 9.8). An 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.

How urgent is CVE-2021-45698?

Priority 57/100. Critical severity; Remotely exploitable, no login, no user action

Related CVEs

CVE-2021-45700 HIGH 7.5 UPGRADE An issue was discovered in the ckb crate before 0.40.0 for Rust
CVE-2021-45699 HIGH 7.5 UPGRADE An issue was discovered in the ckb crate before 0.40.0 for Rust

References

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