# GHSA-j86v-2vjr-fg8f: Etcd Gateway TLS endpoint validation only confirms TCP reachability

> Etcd gateway fails to validate TLS certificates, allowing connections to non-TLS endpoints when using discovery-srv, bypassing security expectations.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 3 Feb 2024
- **Also known as:** GO-2024-2528

## What is GHSA-j86v-2vjr-fg8f?

GHSA-j86v-2vjr-fg8f is a vulnerability in go.etcd.io/etcd, published on 3 Feb 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

### Vulnerability type
Cryptography

### Workarounds
Refer to the [gateway documentation](https://github.com/etcd-io/etcd/blob/master/Documentation/op-guide/gateway.md). The vulnerability was spotted due to unclear documentation of how the gateway handles endpoints validation. 

### Detail
Secure endpoint validation is performed by the etcd gateway start command when the --discovery-srv flag is enabled. However, as currently implemented, it only validates TCP reachability, effectively allowing connections to an endpoint that doesn't accept TLS connections through the HTTPS URL. The auditors has noted that appropriate documentation of this validation functionality plus deprecation of this misleading functionality is an acceptable path forward.

### References
Find out more on this vulnerability in the [security audit report](https://github.com/etcd-io/etcd/blob/master/security/SECURITY_AUDIT.pdf)

### For more information
If you have any questions or comments about this advisory:
* Contact the [etcd security committee](https://github.com/etcd-io/etcd/blob/master/security/security-release-process.md#product-security-committee-psc)

## Which versions are affected by GHSA-j86v-2vjr-fg8f?

6 open source packages ship an affected version, including go.etcd.io/etcd/v3 and go.etcd.io/etcd.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `go.etcd.io/etcd/v3` | Go | All versions | None |
| `go.etcd.io/etcd/v3` | Go | All versions | 3.3.23 |
| `go.etcd.io/etcd/v3` | Go | All versions | 3.3.23 |
| `go.etcd.io/etcd/v3` | Go | From 3.4.0-rc.0 | 3.4.10 |
| `go.etcd.io/etcd/v3` | Go | From 3.4.0-rc.0 | 3.4.10 |
| `go.etcd.io/etcd` | Go | All versions | None |

## How do I fix GHSA-j86v-2vjr-fg8f?

Upgrade go.etcd.io/etcd/v3 to a fixed version for your release line: 3.3.23 or 3.4.10.

## Is GHSA-j86v-2vjr-fg8f being exploited?

There is no known exploitation of GHSA-j86v-2vjr-fg8f in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for GHSA-j86v-2vjr-fg8f and fix it if it is affected.

What it is: GHSA-j86v-2vjr-fg8f is a vulnerability in go.etcd.io/etcd, published on 3 Feb 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of GHSA-j86v-2vjr-fg8f in the wild and no public exploit code.

Affected packages and fixed versions:
- go.etcd.io/etcd/v3 (Go): affected all versions; no fix listed
- go.etcd.io/etcd/v3 (Go): affected all versions; fixed in 3.3.23
- go.etcd.io/etcd/v3 (Go): affected all versions; fixed in 3.3.23
- go.etcd.io/etcd/v3 (Go): affected from 3.4.0-rc.0; fixed in 3.4.10
- go.etcd.io/etcd/v3 (Go): affected from 3.4.0-rc.0; fixed in 3.4.10
- go.etcd.io/etcd (Go): affected all versions; no fix listed

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/GHSA-j86v-2vjr-fg8f/ (Markdown: https://insights.sbomify.com/GHSA-j86v-2vjr-fg8f/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/GHSA-j86v-2vjr-fg8f

---
From sbomify Insights: https://insights.sbomify.com/GHSA-j86v-2vjr-fg8f/
Summaries are generated and may contain mistakes; the official description above is the record.