CVE-2020-26895: Prior to 0.10.0-beta, LND (Lightning Network Daemon) would have accepted a counterparty high-S signature and b

Routine

MEDIUM 5.3REMOTEDOWNGRADE

CVE-2020-26895 is a medium-severity flaw (CVSS 5.3) affecting lightning network daemon. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Prior to 0.10.0-beta, LND (Lightning Network Daemon) would have accepted a counterparty high-S signature and broadcast tx-relay invalid local commitment/HTLC transactions. This can be exploited by any peer with an open channel regardless of the victim situation (e.g., routing node, payment-receiver, or payment-sender). The impact is a loss of funds in certain situations.

Why this priority

Remotely exploitable, no login, no user action

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	5.3 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.7% (top 47%)
CISA exploited list	No
Weakness	CWE-354
Published	2020-10-21
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: lightning network daemon project

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

Am I affected?

Timeline

2020-10-21 02:15 UTCPublished CVE record published
2026-06-17 03:08 UTCUpdated Record last modified

lightning network daemon project lightning network daemon DOWNGRADE

Affected: 0.1 alpha · 0.1.1 alpha · 0.2 alpha · 0.2.1 alpha · 0.3 alpha · 0.4 beta · 0.4.1 beta · 0.4.2 beta

Fixed in: no fixed release known

Safe to downgrade to: a release before 0.1

1. Check installed version

apt-cache policy lightning-network-daemon || rpm -q lightning-network-daemon || lightning-network-daemon --version

2. No fixed release: DOWNGRADE to a release before 0.1 (Debian / Ubuntu)

apt-cache madison lightning-network-daemon sudo apt install lightning-network-daemon=<VERSION_BEFORE_0.1> sudo apt-mark hold lightning-network-daemon

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list lightning-network-daemon sudo dnf downgrade lightning-network-daemon-<VERSION_BEFORE_0.1> sudo dnf versionlock add lightning-network-daemon

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

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-2020-26895?

lightning network daemon: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2020-26895 being exploited?

CVE-2020-26895 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-2020-26895 affect?

CVE-2020-26895 affects lightning network daemon. Severity is medium (CVSS 5.3). Prior to 0.10.0-beta, LND (Lightning Network Daemon) would have accepted a counterparty high-S signature and broadcast tx-relay invalid local commitment/HTLC transactions. This can be exploited by any peer with an open channel regardless of

How urgent is CVE-2020-26895?

Priority 37/100. Remotely exploitable, no login, no user action

Related CVEs

CVE-2022-39389 HIGH 8.2 UPGRADE UPGRADE Lightning Network Daemon (lnd) is an implementation of a lightning bitcoin overlay network node
CVE-2021-41593 HIGH 8.6 UPGRADE Lightning Labs lnd before 0.13.3-beta allows loss of funds because of dust HTLC exposure.
CVE-2020-26896 HIGH 8.2 UPGRADE Prior to 0.11.0-beta, LND (Lightning Network Daemon) had a vulnerability in its invoice database

References

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