# CVE-2022-29188: Smokescreen SSRF via deny list bypass (square brackets) in Smokescreen

> Attackers can bypass the deny list in Smokescreen HTTP proxy by using square brackets around hostnames, allowing access to blocked URLs.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 20 May 2022
- **Updated:** 23 Apr 2025
- **Also known as:** GHSA-qwrf-gfpj-qvj6, GO-2022-0459

## What is CVE-2022-29188?

CVE-2022-29188 is a medium-severity server-side request forgery vulnerability in stripe smokescreen, published on 20 May 2022. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Smokescreen is an HTTP proxy. The primary use case for Smokescreen is to prevent server-side request forgery (SSRF) attacks in which external attackers leverage the behavior of applications to connect to or scan internal infrastructure. Smokescreen also offers an option to deny access to additional (e.g., external) URLs by way of a deny list. There was an issue in Smokescreen that made it possible to bypass the deny list feature by surrounding the hostname with square brackets (e.g. `[example.com]`). This only impacted the HTTP proxy functionality of Smokescreen. HTTPS requests were not impacted. Smokescreen version 0.0.4 contains a patch for this issue.

Weakness: CWE-918 (Server-Side Request Forgery)

## Which versions are affected by CVE-2022-29188?

3 open source packages ship an affected version, including github.com/stripe/smokescreen. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/stripe/smokescreen` | Go | All versions | 0.0.4 |
| `github.com/stripe/smokescreen` | Go | All versions | 0.0.4 |
| `github.com/stripe/smokescreen` | Go | All versions | 0.0.4 |

Products: Stripe Smokescreen.

## How do I fix CVE-2022-29188?

Upgrade github.com/stripe/smokescreen to 0.0.4 or later.

## Is CVE-2022-29188 being exploited?

There is no known exploitation of CVE-2022-29188 in the wild and no public exploit code.

## Other vulnerabilities in stripe smokescreen

- [CVE-2022-24825](https://insights.sbomify.com/CVE-2022-24825/): Smokescreen SSRF via deny list bypass (medium 5.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2022-29188 and fix it if it is affected.

What it is: CVE-2022-29188 is a medium-severity server-side request forgery vulnerability in stripe smokescreen, published on 20 May 2022. 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-2022-29188 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/stripe/smokescreen (Go): affected all versions; fixed in 0.0.4
- github.com/stripe/smokescreen (Go): affected all versions; fixed in 0.0.4
- github.com/stripe/smokescreen (Go): affected all versions; fixed in 0.0.4

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-2022-29188/ (Markdown: https://insights.sbomify.com/CVE-2022-29188/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-29188
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-29188
- OSV: https://osv.dev/vulnerability/CVE-2022-29188

---
From sbomify Insights: https://insights.sbomify.com/CVE-2022-29188/
Summaries are generated and may contain mistakes; the official description above is the record.