# CVE-2013-2503: Security feature bypass in n/a

> Remote HTTP servers can spoof the intended proxy service by manipulating authentication headers, bypassing security controls in Privoxy.

- **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:** Yes
- **Published:** 11 Mar 2013
- **Updated:** 6 Aug 2024
- **Also known as:** DEBIAN-CVE-2013-2503, GHSA-xwv2-6j43-gjcx

## What is CVE-2013-2503?

CVE-2013-2503 is a medium-severity vulnerability in n/a, published on 11 Mar 2013. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Privoxy before 3.0.21 does not properly handle Proxy-Authenticate and Proxy-Authorization headers in the client-server data stream, which makes it easier for remote HTTP servers to spoof the intended proxy service via a 407 (aka Proxy Authentication Required) HTTP status code.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2013-2503?

It affects 1 product.


Products: Privoxy Privoxy.

## How do I fix CVE-2013-2503?

Upgrade to a fixed version.

## Is CVE-2013-2503 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2013-2503 exists.

Public exploit code:

- Privoxy Proxy - Authentication Information Disclosure (exploitdb)

## Other vulnerabilities in n/a

- [CVE-2019-3699](https://insights.sbomify.com/CVE-2019-3699/): Local privilege escalation from user privoxy to root (high 7.7)
- [CVE-2021-44540](https://insights.sbomify.com/CVE-2021-44540/): Denial of service in Privoxy (high 7.5)
- [CVE-2021-44541](https://insights.sbomify.com/CVE-2021-44541/): Denial of service in Privoxy (high 7.5)
- [CVE-2021-44542](https://insights.sbomify.com/CVE-2021-44542/): Denial of service in Privoxy (high 7.5)
- [CVE-2021-20209](https://insights.sbomify.com/CVE-2021-20209/): Denial of service in privoxy (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2013-2503 and fix it if it is affected.

What it is: CVE-2013-2503 is a medium-severity vulnerability in n/a, published on 11 Mar 2013. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2013-2503 exists.

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-2013-2503/ (Markdown: https://insights.sbomify.com/CVE-2013-2503/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2013-2503
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2013-2503
- OSV: https://osv.dev/vulnerability/CVE-2013-2503

---
From sbomify Insights: https://insights.sbomify.com/CVE-2013-2503/
Summaries are generated and may contain mistakes; the official description above is the record.