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mozilla -- "Wrapped" javascript: urls bypass security checks


A Mozilla Foundation Security Advisory reports:

Some security checks intended to prevent script injection were incorrect and could be bypassed by wrapping a javascript: url in the view-source: pseudo-protocol. Michael Krax demonstrated that a variant of his favicon exploit could still execute arbitrary code, and the same technique could also be used to perform cross-site scripting.

Georgi Guninski demonstrated the same flaw wrapping javascript: urls with the jar: pseudo-protocol.

L. David Baron discovered a nested variant that defeated checks in the script security manager.

Workaround: Disable Javascript



portaudit: mozilla -- "Wrapped" javascript: urls bypass security checks

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If you have found a vulnerability in a FreeBSD port not listed in the database, please contact the FreeBSD Security Officer. Refer to "FreeBSD Security Information" for more information.

Oliver Eikemeier <>