Improper Sanitization of Script in an Error Message Web Page
Weakness ID: 81 (Weakness Variant)Status: Incomplete
+ Description

Description Summary

The software receives input from an upstream component, but it does not sanitize or incorrectly sanitizes special characters that could be interpreted as web-scripting elements when they are sent to an error page.

Extended Description

Error pages may include customized 403 Forbidden or 404 Not Found pages.

When an attacker can trigger an error that contains unsanitized input, then cross-site scripting attacks may be possible.

+ Time of Introduction
  • Implementation
  • Operation
+ Applicable Platforms



+ Observed Examples
CVE-2002-0840XSS in default error page from Host: header.
CVE-2002-1053XSS in error message.
CVE-2002-1700XSS in error page from targeted parameter.
+ Potential Mitigations

Do not write user-controlled input to error pages.

Carefully check each input parameter against a rigorous positive specification (white list) defining the specific characters and format allowed. All input should be sanitized, not just parameters that the user is supposed to specify, but all data in the request, including hidden fields, cookies, headers, the URL itself, and so forth. A common mistake that leads to continuing XSS vulnerabilities is to validate only fields that are expected to be redisplayed by the site. We often encounter data from the request that is reflected by the application server or the application that the development team did not anticipate. Also, a field that is not currently reflected may be used by a future developer. Therefore, validating ALL parts of the HTTP request is recommended.

This involves "HTML Entity Encoding" all non-alphanumeric characters from data that was received from the user and is now being written to the request.

With Struts, you should write all data from form beans with the bean's filter attribute set to true.

Additionally, to help mitigate XSS attacks against the user's session cookie, set the session cookie to be HttpOnly. In browsers that support the HttpOnly feature (such as Internet Explorer), this attribute prevents the user's session cookie from being accessed by client-side scripts, including scripts inserted due to a XSS attack.

+ Weakness Ordinalities
(where the weakness is typically related to the presence of some other weaknesses)
+ Relationships
NatureTypeIDNameView(s) this relationship pertains toView(s)
ChildOfWeakness BaseWeakness Base79Failure to Preserve Web Page Structure ('Cross-site Scripting')
Development Concepts (primary)699
Research Concepts (primary)1000
CanAlsoBeWeakness BaseWeakness Base209Information Exposure Through an Error Message
Research Concepts1000
CanAlsoBeWeakness ClassWeakness Class390Detection of Error Condition Without Action
Research Concepts1000
+ Causal Nature


+ Taxonomy Mappings
Mapped Taxonomy NameNode IDFitMapped Node Name
PLOVERXSS in error pages
+ Content History
Submission DateSubmitterOrganizationSource
PLOVERExternally Mined
Modification DateModifierOrganizationSource
2008-07-01Eric DalciCigitalExternal
updated Time of Introduction
2008-09-08CWE Content TeamMITREInternal
updated Description, Relationships, Taxonomy Mappings, Weakness Ordinalities
2008-10-14CWE Content TeamMITREInternal
updated Description
2009-05-27CWE Content TeamMITREInternal
updated Description, Name
Previous Entry Names
Change DatePrevious Entry Name
2008-04-11XSS in Error Pages
2009-05-27Failure to Sanitize Directives in an Error Message Web Page