CVE-2012-4203

6.8 MEDIUM 3% exploit odds Fix listed

What it is

The New Tab page in Mozilla Firefox before 17.0 uses a privileged context for execution of JavaScript code by bookmarklets, which allows user-assisted remote attackers to run arbitrary programs by leveraging a javascript: URL in a bookmark.

At a glance

Exploitability: Can be exploited over the network without logging in. Limited direct impact.
Exploit odds: 3.3% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2012-11-21 12:55 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-06-16 23:44 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 3.3% in the next 30 days (EPSS).
Severity: 6.8 MEDIUM (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2012-11-21 12:55 UTC
Last modified: 2026-06-16 23:44 UTC
Exploit probability: 3.3% · EPSS, next 30 days
Weakness: CWE-264
Record status: Modified

Affected

Mozilla Firefox ≤ 16.0.2
Mozilla Firefox 0.1
Mozilla Firefox 0.2
Mozilla Firefox 0.3
Mozilla Firefox 0.4
Mozilla Firefox 0.5
Mozilla Firefox 0.6
Mozilla Firefox 0.6.1

Attack profile CVSS 2.0 · 6.8

Attack vector: Network
Complexity: Medium
Authentication: None
Confidentiality: Partial
Integrity: Partial
Availability: Partial

Raw vector

AV:N/AC:M/Au:N/C:P/I:P/A:P

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-2012-4203.md and follow it. Check whether this project is affected by CVE-2012-4203. 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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Fix and advisories

References

NVD record · CVE.org record