# CVE-2016-2049: Auth bypass in n/a

> Attackers can hijack user authentication in the JanRain PHP OpenID library by spoofing the HTTP Host header to bypass realm checks.

- **Severity:** High 8.8 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 1 Feb 2016
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-w7j5-jxx6-p7j4, UBUNTU-CVE-2016-2049

## What is CVE-2016-2049?

CVE-2016-2049 is a high-severity authentication bypass vulnerability in n/a, published on 1 Feb 2016. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

examples/consumer/common.php in JanRain PHP OpenID library (aka php-openid) improperly checks the openid.realm parameter against the SERVER_NAME element in the SERVER superglobal array, which might allow remote attackers to hijack the authentication of arbitrary users via vectors involving a crafted HTTP Host header.

Weakness: CWE-284 (Improper Access Control)

## Which versions are affected by CVE-2016-2049?

It affects 1 product.


Products: Janrain Php-Openid.

## How do I fix CVE-2016-2049?

No fix has been published for CVE-2016-2049 yet. Limit exposure of the affected software until one is available.

## Is CVE-2016-2049 being exploited?

There is no known exploitation of CVE-2016-2049 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2013-4701](https://insights.sbomify.com/CVE-2013-4701/): PHP OpenID Library Denial of Service vulnerability (high 7.5)
- [CVE-2011-3707](https://insights.sbomify.com/CVE-2011-3707/): Information disclosure in n/a (medium 5.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2016-2049 and fix it if it is affected.

What it is: CVE-2016-2049 is a high-severity authentication bypass vulnerability in n/a, published on 1 Feb 2016. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2016-2049 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-2016-2049/ (Markdown: https://insights.sbomify.com/CVE-2016-2049/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2016-2049
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2016-2049
- OSV: https://osv.dev/vulnerability/CVE-2016-2049

---
From sbomify Insights: https://insights.sbomify.com/CVE-2016-2049/
Summaries are generated and may contain mistakes; the official description above is the record.