Is this a regression of http://bugs.limesurvey.org/view.php?id=6536 ?

http://manual.limesurvey.org/Expression_Manager#Security_issue
{if(1 lt 2,"less","more")}

ELse , need to find a way :)

Disabling the HTML/CSS filter at global settings -> security should solve this issue though I agree that this is no real fix but should be fixed at the Limesurvey code if possible.

Better is to use lt,le,gt and ge (no need to disable xss) . But yes, try to find a fix.

Just my two cents:
As far as I can tell the code checks questions with an HTMLPurifier before doing anything else. How about first validating it (or at least containing expressions) with the "expression-manager" (if such a thing exists in the code). If an expression fails that validation it can/should be purified...

No,

Because we need to purify
<script>alert('XSS')</script>{SOMETHING}

Or
{if(1 lt 2,"<span onmouseover='alert(XSS)'>mouse hover</span>","more")}

Hi DenisChenu,

I know why this purification is necessary. But
{if(1 lt 2,"<span onmouseover='alert(XSS)'>mouse hover</span>","more")}
is not a valid expression so it has to be purified.
Whereas
{if(1 < 2,"less","more")}
is a valid expression and has no need to be purified.

In other words: a valid expression can't contain a XSS, can it? So there is no need to purify it.

I guess a question may contain a mixture of expressions and normal text so it gets complicated...

Starting point :
echo preg_replace("/{(.)( > )(.)}/","{"."$1 > $3"."}",preg_replace("/{(.)( < )(.)}/","{"."$1 < $3"."}",purify($string)));

But need more control (na space, no lf after { or before }.

And need to test some update too "EM string"

{if(1 < 2," < "," > ")}
=>
{if(1 < 2," & lt ; "," & gt ; ")}

In https://github.com/LimeSurvey/LimeSurvey/pull/173 but maybe more test to find if there are a way for user to add XSS or some other broken security.

Another solution :
https://github.com/LimeSurvey/LimeSurvey/pull/174

PS: {if(1 lt 2,"<span onmouseover='alert(XSS)'>mouse hover</span>","more")} IS a valid expression.

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