# CVE-2020-15112: Improper Input Validation in etcd

> An attacker can cause a runtime panic and crash an etcd consensus participant by providing an invalid entry index during WAL reading.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 5 Aug 2020
- **Updated:** 4 Aug 2024
- **Also known as:** AZL-6389, DEBIAN-CVE-2020-15112, UBUNTU-CVE-2020-15112

## What is CVE-2020-15112?

CVE-2020-15112 is a medium-severity denial of service vulnerability in Fedoraproject Fedora, published on 5 Aug 2020. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

In etcd before versions 3.3.23 and 3.4.10, it is possible to have an entry index greater then the number of entries in the ReadAll method in wal/wal.go. This could cause issues when WAL entries are being read during consensus as an arbitrary etcd consensus participant could go down from a runtime panic when reading the entry.

Weakness: CWE-129 (Improper Validation of Array Index), CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2020-15112?

It affects 2 products.


Products: Etcd Etcd, Fedoraproject Fedora.

## How do I fix CVE-2020-15112?

Upgrade to a fixed version.

## Is CVE-2020-15112 being exploited?

There is no known exploitation of CVE-2020-15112 in the wild and no public exploit code.

## Other vulnerabilities in Fedoraproject Fedora

- [CVE-2021-28235](https://insights.sbomify.com/CVE-2021-28235/): Etcd-io Improper Authentication vulnerability (critical 9.8)
- [CVE-2026-33413](https://insights.sbomify.com/CVE-2026-33413/): etcd: Authorization bypasses in multiple APIs (high 8.8)
- [CVE-2022-34038](https://insights.sbomify.com/CVE-2022-34038/): Denial of service in n/a (high 7.5)
- [CVE-2018-16886](https://insights.sbomify.com/CVE-2018-16886/): go.etcd.io/etcd Authentication Bypass (medium 6.8)
- [CVE-2026-59818](https://insights.sbomify.com/CVE-2026-59818/): etcd: gRPC client listener does not enforce `--client-crl-file` certificate revocation (medium 6.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-15112 and fix it if it is affected.

What it is: CVE-2020-15112 is a medium-severity denial of service vulnerability in Fedoraproject Fedora, published on 5 Aug 2020. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2020-15112 in the wild and no public exploit code.

Affected product: Fedoraproject Fedora. 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-2020-15112/ (Markdown: https://insights.sbomify.com/CVE-2020-15112/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-15112
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-15112
- OSV: https://osv.dev/vulnerability/CVE-2020-15112

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From sbomify Insights: https://insights.sbomify.com/CVE-2020-15112/
Summaries are generated and may contain mistakes; the official description above is the record.