Bug 2548551

Summary:	CVE-2026-106446 boost: Handlebars: JavaScript Injection via AST Type Confusion in compile (Program.blockParams) [fedora-all]
Product:	[Fedora] Fedora	Reporter:	Srikanth Balasubramanian <sbalasub>
Component:	boost	Assignee:	Jonathan Wakely <jwakely>
Status:	CLOSED NOTABUG	QA Contact:	Fedora Extras Quality Assurance <extras-qa>
Severity:	high	Docs Contact:
Priority:	high
Version:	rawhide	CC:	denis.arnaud_fedora, jwakely, laurent.rineau__fedora, mcermak, ppalka
Target Milestone:	---	Keywords:	Security, SecurityTracking
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:	{"flaws": ["7b898470-2410-4fc0-a57a-740d9bab91f2"]}
Fixed In Version:		Doc Type:	---
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2026-10-09 13:14:37 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:
Bug Blocks:	2547120

Description Srikanth Balasubramanian 2026-10-09 12:28:45 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.

Comment 1 Jonathan Wakely 2026-10-09 13:14:37 UTC

As I have said repeatedly:

The CVE does not affect Boost. The Node modules are only used to generate HTML files during preparation of the release tarball, and are not used during the RPM build and are not part of the installed RPMs.

I checked this with upstream and was told "The npm packages are only required at doc build time, so it makes
sense to not include them in the release tarball."
https://lists.boost.org/archives/list/boost@lists.boost.org/thread/APKJIASXU2DLQMGYIQR4JOMJE5CB56KB/

The Boost 1.92.0 release will not include those files in the release tarball at all, due to https://github.com/boostorg/release-tools/pull/111 which was already changed in March. That PR says "Remove "doc/node_modules" from libraries after the build. Since that directory adds extra MBs, and isn't needed."