CVE-2006-2786

What it is

HTTP response smuggling vulnerability in Mozilla Firefox and Thunderbird before 1.5.0.4, when used with certain proxy servers, allows remote attackers to cause Firefox to interpret certain responses as if they were responses from two different sites via (1) invalid HTTP response headers with spaces between the header name and the colon, which might not be ignored in some cases, or (2) HTTP 1.1 headers through an HTTP 1.0 proxy, which are ignored by the proxy but processed by the client.

At a glance

Exploitability

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

Exploit odds

1.8% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2006-06-02 20:02 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-16 22:25 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 1.8% in the next 30 days (EPSS).
• Severity: 2.6 LOW (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2006-06-02 20:02 UTC

Last modified

2026-06-16 22:25 UTC

Exploit probability

1.8% · EPSS, next 30 days

Record status

Modified

Affected

• Mozilla Firefox ≤ 1.5.0.3
• Mozilla Thunderbird ≤ 1.5.0.3

Attack profile CVSS 2.0 · 2.6

Attack vector

Network

Complexity

High

Authentication

None

Confidentiality

None

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-2006-2786.md and follow it. Check whether this project is affected by CVE-2006-2786. 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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