# CVE-2011-1766: Auth bypass in n/a

> Remote attackers can bypass authentication in MediaWiki by exploiting cached data when wgBlockDisablesLogin is enabled, allowing unauthorized access.

- **Severity:** Medium 5.8 (`AV:N/AC:M/Au:N/C:P/I:P/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 23 May 2011
- **Updated:** 6 Aug 2024
- **Also known as:** GHSA-m9hp-7333-625v

## What is CVE-2011-1766?

CVE-2011-1766 is a medium-severity authentication bypass vulnerability in Mediawiki Mediawiki, published on 23 May 2011. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

includes/User.php in MediaWiki before 1.16.5, when wgBlockDisablesLogin is enabled, does not clear certain cached data after verification of an auth token fails, which allows remote attackers to bypass authentication by creating crafted wikiUserID and wikiUserName cookies, or by leveraging an unattended workstation.

Weakness: CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2011-1766?

It affects 1 product.


Products: Mediawiki Mediawiki.

## How do I fix CVE-2011-1766?

No fix has been published for CVE-2011-1766 yet. Limit exposure of the affected software until one is available.

## Is CVE-2011-1766 being exploited?

There is no known exploitation of CVE-2011-1766 in the wild and no public exploit code.

## Other vulnerabilities in Mediawiki Mediawiki

- [CVE-2023-37303](https://insights.sbomify.com/CVE-2023-37303/): Denial of service in n/a (critical 9.8)
- [CVE-2022-29904](https://insights.sbomify.com/CVE-2022-29904/): SQL injection in n/a (critical 9.8)
- [CVE-2022-29906](https://insights.sbomify.com/CVE-2022-29906/): Missing authorization in n/a (critical 9.8)
- [CVE-2022-28205](https://insights.sbomify.com/CVE-2022-28205/): Business logic in n/a (critical 9.8)
- [CVE-2022-28206](https://insights.sbomify.com/CVE-2022-28206/): Missing authorization in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2011-1766 and fix it if it is affected.

What it is: CVE-2011-1766 is a medium-severity authentication bypass vulnerability in Mediawiki Mediawiki, published on 23 May 2011. 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-2011-1766 in the wild and no public exploit code.

Affected product: Mediawiki Mediawiki. 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-2011-1766/ (Markdown: https://insights.sbomify.com/CVE-2011-1766/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2011-1766
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2011-1766
- OSV: https://osv.dev/vulnerability/CVE-2011-1766

---
From sbomify Insights: https://insights.sbomify.com/CVE-2011-1766/
Summaries are generated and may contain mistakes; the official description above is the record.