# CVE-2020-26291: Hostname spoofing in URI.js

> Attackers can spoof hostnames in URI.js, potentially bypassing security checks like allowlists or causing SSRF and open redirects.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N`)
- **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:** 30 Dec 2020
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-3329-pjwv-fjpg

## What is CVE-2020-26291?

CVE-2020-26291 is a medium-severity vulnerability in medialize URI.js, published on 30 Dec 2020. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

URI.js is a javascript URL mutation library (npm package urijs). In URI.js before version 1.19.4, the hostname can be spoofed by using a backslash (`\`) character followed by an at (`@`) character. If the hostname is used in security decisions, the decision may be incorrect. Depending on library usage and attacker intent, impacts may include allow/block list bypasses, SSRF attacks, open redirects, or other undesired behavior. For example the URL `https://expected-example.com\@observed-example.com` will incorrectly return `observed-example.com` if using an affected version. Patched versions correctly return `expected-example.com`. Patched versions match the behavior of other parsers which implement the WHATWG URL specification, including web browsers and Node's built-in URL class. Version 1.19.4 is patched against all known payload variants. Version 1.19.3 has a partial patch but is still vulnerable to a payload variant.]

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2020-26291?

2 open source packages ship an affected version, including urijs. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `urijs` | npm | All versions | 1.19.4 |
| `urijs` | npm | All versions | 1.19.4 |

Products: Uri.js Project Uri.js.

## How do I fix CVE-2020-26291?

Upgrade urijs to 1.19.4 or later.

## Is CVE-2020-26291 being exploited?

There is no known exploitation of CVE-2020-26291 in the wild and no public exploit code.

## Other vulnerabilities in medialize URI.js

- [CVE-2022-0868](https://insights.sbomify.com/CVE-2022-0868/): Open Redirect in medialize/uri.js (high 8.0)
- [CVE-2021-27516](https://insights.sbomify.com/CVE-2021-27516/): URIjs Hostname spoofing via backslashes in URL (high 7.5)
- [CVE-2022-1243](https://insights.sbomify.com/CVE-2022-1243/): CRHTLF can lead to invalid protocol extraction potentially leading to XSS in medialize/uri.js (high 7.2)
- [CVE-2022-1233](https://insights.sbomify.com/CVE-2022-1233/): URL Confusion When Scheme Not Supplied in medialize/uri.js (medium 6.5)
- [CVE-2022-24723](https://insights.sbomify.com/CVE-2022-24723/): Improper Input Validation in URI.js (medium 5.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-26291 and fix it if it is affected.

What it is: CVE-2020-26291 is a medium-severity vulnerability in medialize URI.js, published on 30 Dec 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-2020-26291 in the wild and no public exploit code.

Affected packages and fixed versions:
- urijs (npm): affected all versions; fixed in 1.19.4
- urijs (npm): affected all versions; fixed in 1.19.4

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-2020-26291/ (Markdown: https://insights.sbomify.com/CVE-2020-26291/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-26291
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-26291
- OSV: https://osv.dev/vulnerability/CVE-2020-26291

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-26291/
Summaries are generated and may contain mistakes; the official description above is the record.