# CVE-2020-26896: Business logic in n/a

> A malicious peer can steal intercepted HTLC funds and compromise receiver privacy by exploiting a preimage release logic flaw in LND.

- **Severity:** High 8.2 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 21 Oct 2020
- **Updated:** 4 Aug 2024

## What is CVE-2020-26896?

CVE-2020-26896 is a high-severity vulnerability in n/a, published on 21 Oct 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Prior to 0.11.0-beta, LND (Lightning Network Daemon) had a vulnerability in its invoice database. While claiming on-chain a received HTLC output, it didn't verify that the corresponding outgoing off-chain HTLC was already settled before releasing the preimage. In the case of a hash-and-amount collision with an invoice, the preimage for an expected payment was instead released. A malicious peer could have deliberately intercepted an HTLC intended for the victim node, probed the preimage through a colluding relayed HTLC, and stolen the intercepted HTLC. The impact is a loss of funds in certain situations, and a weakening of the victim's receiver privacy.

Weakness: CWE-354 (Improper Validation of Integrity Check Value)

## Which versions are affected by CVE-2020-26896?

It affects 1 product.


Products: Lightning Network Daemon Project Lightning Network Daemon.

## How do I fix CVE-2020-26896?

No fix has been published for CVE-2020-26896 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-26896 being exploited?

There is no known exploitation of CVE-2020-26896 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2021-41593](https://insights.sbomify.com/CVE-2021-41593/): Business logic in n/a (high 8.6)
- [CVE-2020-26895](https://insights.sbomify.com/CVE-2020-26895/): Business logic in n/a (medium 5.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-26896 and fix it if it is affected.

What it is: CVE-2020-26896 is a high-severity vulnerability in n/a, published on 21 Oct 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2020-26896 in the wild and no public exploit code.

Affected product: n/a. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2020-26896/ (Markdown: https://insights.sbomify.com/CVE-2020-26896/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-26896
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-26896
- OSV: https://osv.dev/vulnerability/CVE-2020-26896

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-26896/
Summaries are generated and may contain mistakes; the official description above is the record.