CVE-2018-17075 in HTML Package
Summary
by MITRE
The html package (aka x/net/html) before 2018-07-13 in Go mishandles "in frameset" insertion mode, leading to a "panic: runtime error" for html.Parse of <template><object>, <template><applet>, or <template><marquee>. This is related to HTMLTreeBuilder.cpp in WebKit.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 05/16/2023
The vulnerability CVE-2018-17075 represents a critical runtime error in the Go programming language's html package, specifically affecting versions prior to 2018-07-13. This issue manifests as a panic condition during HTML parsing operations when processing certain malformed template elements containing object, applet, or marquee tags. The flaw originates from the HTMLTreeBuilder.cpp implementation within WebKit, indicating a cross-platform compatibility issue that affects Go's HTML parsing implementation. The vulnerability demonstrates how HTML parsing libraries can be susceptible to malformed input that triggers internal state management failures, particularly when dealing with nested template elements and specific embedding tags.
The technical root cause of this vulnerability lies in the improper handling of "in frameset" insertion mode within the HTML parsing algorithm. When the html.Parse function encounters a sequence such as <template><object>, <template><applet>, or <template><marquee>, the parser enters an inconsistent state where it fails to properly transition between insertion modes. This mismanagement results in a runtime panic that crashes the application, effectively creating a denial of service condition. The vulnerability specifically targets the state machine implementation that governs how HTML elements are parsed and structured, where the insertion mode transitions fail to account for the complex nesting scenarios involving template elements.
The operational impact of this vulnerability extends beyond simple application crashes, as it can be exploited in web applications that process untrusted HTML input or user-generated content. Attackers could craft malicious HTML payloads that trigger the panic condition, causing service disruption for applications relying on Go's html package for parsing. This vulnerability affects any system where Go applications process HTML content, particularly web applications, content management systems, or any software that uses the standard library's html parsing functionality. The exploitability is relatively straightforward, requiring only the generation of malformed HTML sequences that trigger the specific parsing path.
Security professionals should note that this vulnerability aligns with CWE-129, which addresses improper handling of input boundaries, and relates to ATT&CK technique T1203, which covers exploitation of input validation weaknesses. The vulnerability also demonstrates the importance of robust error handling in parsing libraries and highlights how seemingly benign HTML structures can trigger catastrophic failures. Organizations should immediately update their Go environments to versions released after July 13, 2018, to mitigate this risk. Additionally, implementing proper input validation and sanitization measures can provide defense-in-depth protection against similar parsing vulnerabilities, particularly in applications that process untrusted HTML content from external sources or user inputs.