Search the knowledgebase


Advisory: Combinations of right-to-left text and negative margins can crash Opera

Summary

Combinations of right-to-left text and negative margins in HTML code can crash Opera.

Severity: Not a security issue.

Problem description

Right-to-left scripts, for example Arabic, are handled by the so-called "bidi" (bidirectional text) support in Opera. Bidi allows left-to-right and right-to-left scripts to be combined in the same document, even on the same line.

A negative margin value inside a block containing right-to- left text can cause the layout engine to follow a null pointer, leading to a crash.

Opera's response

This crash can not be used to run arbitrary code and should not be considered a security issue.

Browse through articles in the same categories: advisory