CVE-2011-3656

Severity: medium (CVSS 6.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.8% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-06-02 · updated 2026-06-16
Weakness: CWE-79

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.

Affected products

Mozilla Firefox: before 3.6.24; from 4.0 through 7.0 — fixed in 3.6.24

How to fix

Upgrade to a fixed version: Mozilla Firefox 3.6.24. Check the vendor advisory for mitigations.

References

https://bugzilla.mozilla.org/show_bug.cgi?id=667907
https://bugzilla.mozilla.org/show_bug.cgi?id=667907

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