CVE-2013-2503

What it is

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.

At a glance

Exploitability

Can be exploited over the network without logging in. Limited direct impact.

Exploit odds

4.6% chance of exploitation in the next 30 days (EPSS).

Fix

No patch or advisory is linked yet. Look at mitigations or restrict exposure.

Timeline

1. 2013-03-11 17:55 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-16 23:53 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 4.6% in the next 30 days (EPSS).
• Severity: 5.8 MEDIUM (CVSS).
• Fix: none linked yet, which raises it.

Details

Published

2013-03-11 17:55 UTC

Last modified

2026-06-16 23:53 UTC

Exploit probability

4.6% · EPSS, next 30 days

Weakness

CWE-20 · Improper input validation

Record status

Modified

Affected

• Privoxy ≤ 3.0.20
• Privoxy 2.9.0
• Privoxy 2.9.1
• Privoxy 2.9.2
• Privoxy 2.9.3
• Privoxy 2.9.11
• Privoxy 2.9.12
• Privoxy 2.9.13

Attack profile CVSS 2.0 · 5.8

Attack vector

Network

Complexity

Medium

Authentication

None

Confidentiality

Partial

Integrity

Partial

Availability

None

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2013-2503.md and follow it. Check whether this project is affected by CVE-2013-2503. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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