CVE-2021-41591: ACINQ Eclair before 0.6.3 allows loss of funds because of dust HTLC exposure.

Q: How do I fix CVE-2021-41591?

eclair: upgrade to 0.6.3. Exact commands for each OS are on this page.

Q: Is CVE-2021-41591 being exploited?

CVE-2021-41591 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-2021-41591 affect?

CVE-2021-41591 affects eclair. Severity is critical (CVSS 9.4). ACINQ Eclair before 0.6.3 allows loss of funds because of dust HTLC exposure.

Q: How urgent is CVE-2021-41591?

Priority 62/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

This week

CRITICAL 9.4REMOTEUPGRADE

CVE-2021-41591 is a critical-severity flaw (CVSS 9.4) affecting eclair. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

ACINQ Eclair before 0.6.3 allows loss of funds because of dust HTLC exposure.

Why this priority

Critical severity
Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.4 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.7% (top 23%)
CISA exploited list	No
Weakness	CWE-770
Published	2021-10-04
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: acinq

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

Am I affected?

Timeline

2021-10-04 17:15 UTCPublished CVE record published
2026-06-17 04:08 UTCUpdated Record last modified

acinq eclair UPGRADE

Affected: < 0.6.3

Fixed in: 0.6.3

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to 0.6.3 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade eclair

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-2021-41591?

eclair: upgrade to 0.6.3. Exact commands for each OS are on this page.

Is CVE-2021-41591 being exploited?

CVE-2021-41591 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-2021-41591 affect?

CVE-2021-41591 affects eclair. Severity is critical (CVSS 9.4). ACINQ Eclair before 0.6.3 allows loss of funds because of dust HTLC exposure.

How urgent is CVE-2021-41591?

Priority 62/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

Related CVEs

CVE-2019-13000 HIGH 7.5 UPGRADE Eclair through 0.3 allows attackers to trigger loss of funds because of Incorrect Access Control

References

← Back to latest CVEs