CVE-2020-26895
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 · uneditedPrior 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.
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 confidenceIn LND versions prior to 0.10.0-beta, the node incorrectly validated counterparty signatures by accepting high-S values, which are invalid per BIP-62. This allowed any peer with an open channel to provide malicious signatures that would be accepted and broadcast as invalid commitment or HTLC transactions, potentially causing loss of funds for 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= 0.1= 0.1.1= 0.2= 0.2.1= 0.3= 0.4= 0.4.1= 0.4.2= 0.5= 0.5.1= 0.5.2= 0.6CVSS 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
- None
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/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 installed LND versionRun `lncli version` or inspect the LND binary with `--version` to obtain the exact version stringAffected if The version is 0.6 or any version from 0.1 through 0.6 (including 0.1, 0.1.1, 0.2, 0.2.1, 0.3, 0.4, 0.4.1, 0.4.2, 0.5, 0.5.1, 0.5.2, 0.6)
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Verify open channel countRun `lncli listchannels` to enumerate active channelsAffected if There are one or more open channels with remote peers, as the vulnerability is exploitable by any counterparty with an active channel
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Review recent commitment transactionsRun `lncli listpaginated --type=all` or query the channel database for recent commitment transactions to identify any that may have been broadcast with invalid high-S signaturesAffected if Any commitment or HTLC transactions were accepted from peers that were subsequently rejected by the network or flagged as invalid by other nodes
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Inspect pending HTLCsRun `lncli listpendingchannels` to examine any pending HTLCs that may have been submitted with malformed signaturesAffected if There are pending HTLCs that were not resolved or were stuck due to signature validation issues
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Check peer node behaviorReview node logs and run `lncli getnodeinfo` on connected peers to identify any that are propagating invalid signatures or have been flagged by the networkAffected if Connected peers have been identified as broadcasting invalid commitment transactions or have been isolated by other nodes for signature violations
If the installed LND version is 0.6 or earlier and there are open channels with peers, the environment is potentially affected by this vulnerability.
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 dataUpgrade LND to version 0.10.0-beta or later, which implements proper high-S signature validation. Before upgrading, review all open channels for any anomalous activity.
- Consultation2.0 h
- Implementation1.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-26895 — 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-2020-26895 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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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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