CVE-2011-3656

Name: CVE-2011-3656
Creator: NVD / NIST
Published: 2021-06-02T17:15:07.67+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.1/10EPSS 0.76%

Last modified Jun 16, 2026

CVE-2011-3656 is a medium-severity vulnerability rated 6.1/10 on the CVSS scale. Cross-site scripting (XSS) vulnerability in Mozilla Firefox before 3.6.24 and 4.x through 7 allows remote attackers to inject arbitrary web script or HTML via vectors involving HTTP 0.9 errors, non-default ports, and content-sniffing.. EPSS estimates a 0.76% chance of exploitation in the next 30 days.

Description

Cross-site scripting (XSS) vulnerability in Mozilla Firefox before 3.6.24 and 4.x through 7 allows remote attackers to inject arbitrary web script or HTML via vectors involving HTTP 0.9 errors, non-default ports, and content-sniffing.

Metrics

CVSS 3.1

6.1/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

EPSS Probability

0.76%

50.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-79

Affected Software

Vendor	Product	Versions
Mozilla	Firefox	< 3.6.24
Mozilla	Firefox	>= 4.0, <= 7.0

References

https://bugzilla.mozilla.org/show_bug.cgi?id=667907Issue Tracking, Vendor Advisory
https://bugzilla.mozilla.org/show_bug.cgi?id=667907Issue Tracking, Vendor Advisory

Timeline

Published: Jun 2, 2021
Last Modified: Jun 16, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2011-3656?

How severe is CVE-2011-3656?

CVE-2011-3656 has a CVSS score of 6.1/10 (MEDIUM severity). The EPSS model estimates a 0.76% probability of exploitation in the next 30 days.

How do I fix CVE-2011-3656?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2011-3656?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST