HTTP Header Injection in LiteSpeed Web Server


Advisory by Netsparker (now Invicti)
Name: HTTP Header Injection in LiteSpeed Web Server
Affected Software: LiteSpeed Web Server
Affected Versions: v5.1.0 and possibly below
Vendor Homepage:
Vulnerability Type: HTTP Header Injection
Severity: Medium
Status: Fixed
CVE-ID: 2016-5110
Invicti Advisory Reference: NS-16-001


While testing Invicti, we spotted an HTTP Header Injection vulnerability in LiteSpeed Web Server.

LiteSpeed Web Server v5.1.0 and possibly below are affected if mod_userdir is enabled. This vulnerability can be exploited in various ways depending on the application.

Technical Details

Proof of Concept URL for HTTP Header Injection in LiteSpeed Web Server:


Advisory Timeline

15 Jan 2016 – First Contact
18 Jan 2016 – Vendor Fixed
20 Jan 2016 – Advisory Released


Patch released by LiteSpeed and announced here: Download the latest version.

Credits & Authors

These issues have been discovered by Ziyahan Albeniz while testing Invicti Web Application Security Scanner.

About Invicti

Invicti Security is transforming the way web applications are secured. Invicti empowers organizations in every industry to scale their overall security operations, make the best use of their security resources, and engage developers in helping to improve their overall security posture.