Bug 2548558

Summary: CVE-2026-106446 python-robotframework: Handlebars: JavaScript Injection via AST Type Confusion in compile (Program.blockParams) [fedora-all]
Product: [Fedora] Fedora Reporter: Srikanth Balasubramanian <sbalasub>
Component: python-robotframeworkAssignee: fedepell <fede>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: rawhideCC: fede, jkadlcik, pszubiak
Target Milestone: ---Keywords: Security, SecurityTracking
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Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["7b898470-2410-4fc0-a57a-740d9bab91f2"]}
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Bug Blocks: 2547120    

Description Srikanth Balasubramanian 2026-10-09 12:30:17 UTC 
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

Handlebars provides the power necessary to let users build semantic templates. From 4.0.0 until 4.7.10, Handlebars.compile() and Handlebars.precompile() accept pre-parsed AST objects while validating only selected PathExpression, NumberLiteral, and BooleanLiteral values. This issue bypasses the AST validation introduced in version 4.7.9 for CVE-2026-33937. An attacker who can supply an object instead of a template string can place JavaScript expressions in unchecked values such as Program.blockParams.length, a non-PathExpression parameter depth, a non-string StringLiteral.value, or a non-string PathExpression.original. The compiler emits those values into generated JavaScript, causing code execution in the server process when compile output renders or wherever precompile output is loaded. Applications that pass only template strings are not affected. This issue is fixed in version 4.7.10.