Longhorn PHP 2023 - Call for Papers


(PHP 5 >= 5.2.11, PHP 7, PHP 8)

libxml_disable_entity_loaderDisable the ability to load external entities


This function has been DEPRECATED as of PHP 8.0.0. Relying on this function is highly discouraged.


libxml_disable_entity_loader(bool $disable = true): bool

Disable/enable the ability to load external entities. Note that disabling the loading of external entities may cause general issues with loading XML documents. However, as of libxml 2.9.0 entity substitution is disabled by default, so there is no need to disable the loading of external entities, unless there is the need to resolve internal entity references with LIBXML_NOENT. Generally, it is preferable to use libxml_set_external_entity_loader() to suppress loading of external entities.



Disable (true) or enable (false) libxml extensions (such as DOM, XMLWriter and XMLReader) to load external entities.

Return Values

Returns the previous value.

See Also

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User Contributed Notes 7 notes

suconghou at gmail dot com
2 years ago
In PHP 8.0 and later, PHP uses libxml versions from 2.9.0, libxml_disable_entity_loader is deprecated.
so it is now safe to remove all `libxml_disable_entity_loader` calls on php8

if you want Backwards Compatibility

use this snippet

if (\PHP_VERSION_ID < 80000) {
vavra at 602 dot cz
5 years ago
If is called

, it causes that new SoapClient(.) fails with

SOAP-ERROR: Parsing WSDL: Couldn't load from 'D:\path/dm_operations.wsdl' : failed to load external entity "D:\path/dm_operations.wsdl

because this wsdl imports a xsd as an another external file.
Tested on php 7.1.12, win x64.
editor at geekkb.com
1 month ago
There is an extra \ should be deleted before PHP_VERSION_ID in the code which suconghou posted 2 years ago.

if (PHP_VERSION_ID < 80000) {
phofstetter at sensational dot ch
9 years ago
Be mindful that this also disables url loading in simplexml_load_file() and likely other libxml based functions that deal with URLs
11 years ago
Using this function you can prevent a vulnerable to Local and Remote File Inclusion attacks.

You'll see it in an example where I load and validate the following string:

<!DOCTYPE scan [<!ENTITY test SYSTEM "php://filter/read=convert.base64-encode/resource=/etc/passwd">]>

One way to prevent that the file in given back is to set this value to 0.
Please take a closer look at the release of symfony 2.0.11
brendan at bloodbone dot ws
9 years ago
This also seems to have an impact on <xsl:import /> statements if this is applied when loading XSLT for the XSLTProcessor class.
daschtour at me dot com
9 years ago
This function was reported to be not thread safe. So this might affect php-scripts on the same server.
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