CVE-2026-72925
Received Received - Intake

JSON Parsing Flaw in SWC HTML Minifier Enables XSS

Publication date: 2026-08-11

Last updated on: 2026-08-11

Assigner: GitHub, Inc.

Description
SWC is a TypeScript / JavaScript compiler written in Rust. Prior to @swc/html 1.15.47-nightly-20260729.1 and swc_html_minifier 59.0.0, the minifyJson processing in crates/swc_html_minifier/src/lib.rs parsed and serialized attacker-controlled JSON in application/json and application/ld+json script elements without the escape_json_for_html_script behavior to re-escape less-than signs, allowing a closing script sequence to terminate the element early and execute script in the generated page's origin. This issue is fixed in @swc/html 1.15.47-nightly-20260729.1 and swc_html_minifier 59.0.0.

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Meta Information

Published
2026-08-11
Last Modified
2026-08-11
Generated
2026-08-11
AI Q&A
2026-08-11
EPSS Evaluated
N/A
NVD
CVE-2026-72925
EUVD
EUVD-2026-56179

Affected Vendors & Products

Showing 4 associated CPEs
Vendor Product Version / Range
swc_project swc_html to 1.15.47-nightly-20260729.1 (exc)
swc_project swc_html_minifier to 59.0.0 (exc)
swc_project html to 1.15.47-nightly-20260729.1 (exc)
swc_project html_minifier to 59.0.0 (exc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-79 The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.
CWE-116 The product prepares a structured message for communication with another component, but encoding or escaping of the data is either missing or done incorrectly. As a result, the intended structure of the message is not preserved.

Attack-Flow Graph

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Executive Summary

This vulnerability involves the SWC HTML minifier improperly handling JSON embedded in script elements. When minifying JSON, the serializer converts escaped less-than signs like \u003C into literal < characters. If the JSON contains an escaped </script> sequence, the HTML parser may prematurely close the script tag, allowing attacker-controlled JSON to inject active markup and execute scripts in the page's origin.

Detection Guidance

To detect this vulnerability, check if your system uses vulnerable versions of @swc/html (before 1.15.47-nightly-20260729.1) or swc_html_minifier (before 59.0.0). Inspect package.json or dependency files for these versions. No specific commands are provided in the context to actively detect exploitation.

Impact Analysis

An attacker could exploit this to inject malicious scripts into web pages processed by vulnerable SWC versions. This could lead to cross-site scripting (XSS) attacks, allowing theft of sensitive data, session hijacking, or defacement of affected websites. Users of applications using these SWC components may be exposed to these risks.

Compliance Impact

This vulnerability could lead to unauthorized script execution, potentially violating data protection requirements under GDPR (e.g., Article 32 security of processing) and HIPAA (e.g., safeguards for protected health information). Organizations may face compliance violations if user data is compromised due to XSS attacks exploiting this flaw.

Mitigation Strategies

Upgrade to @swc/html 1.15.47-nightly-20260729.1 or later and swc_html_minifier 59.0.0 or later. Alternatively, disable JSON minification by setting minifyJson to false as a temporary workaround.

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