CVE-2026-72925

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.

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.

Impact

@swc/html minifies JSON contained in script elements such as application/json and application/ld+json by parsing and serializing the JSON value.

Before the patched versions, JSON serialization could convert escaped less-than signs such as \u003C into literal < characters. If the JSON contained an escaped </script> sequence, the generated HTML could terminate the containing script element early because HTML tokenization occurs before the JSON is consumed.

Applications that minify HTML containing attacker-controlled JSON data could therefore transform inert data into active markup. A crafted payload could execute script in the origin of the generated page.

Patches

The issue is fixed in:

• @swc/html 1.15.47
• swc_html_minifier 59.0.0

The minifier now re-escapes less-than signs after JSON serialization, preserving the script element boundary.

Workarounds

Users who cannot upgrade can disable JSON minification with:

await minify(html, {
  minifyJson: false,
});

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.

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.

Impact

@swc/html minifies JSON contained in script elements such as application/json and application/ld+json by parsing and serializing the JSON value.

Before the patched versions, JSON serialization could convert escaped less-than signs such as \u003C into literal < characters. If the JSON contained an escaped </script> sequence, the generated HTML could terminate the containing script element early because HTML tokenization occurs before the JSON is consumed.

Applications that minify HTML containing attacker-controlled JSON data could therefore transform inert data into active markup. A crafted payload could execute script in the origin of the generated page.

Patches

The issue is fixed in:

• @swc/html 1.15.47
• swc_html_minifier 59.0.0

The minifier now re-escapes less-than signs after JSON serialization, preserving the script element boundary.

Workarounds

Users who cannot upgrade can disable JSON minification with:

await minify(html, {
  minifyJson: false,
});