Vulnerabilities in pkg:npm/@swc/html

PACKAGE
Advisory Identifier: GHSA-5qr2-v392-m9g8
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Advisory Summary

CVE-2026-72925 is a MODERATE (CVSS 6.1) swc html minifier may allow vulnerability (CWE-116: Improper Encoding or Escaping of Output) affecting @swc/html libraries in the npm ecosystem. The issue involves swc html minifier may allow script element breakout when minifying embedded json. Remediation is available by upgrading affected packages to version 1.15.47-nightly-20260729.1, 59.0.0.

1 Known Advisory Record(s)
Package Vulnerability Intelligence

pkg:npm/@swc/html

1 Known Advisory Record(s)

Vulnerability advisories affecting package pkg:npm/@swc/html. Select an advisory below to view technical details or fixes.

Advisory ID CVE / NVD Severity Summary
GHSA-5qr2-v392-m9g8 CVE-2026-72925 MODERATE SWC HTML minifier may allow script element breakout when minifying embedded JSON

CVE-2026-72925 at a Glance

CVE Identifier CVE-2026-72925
GHSA Identifier GHSA-5qr2-v392-m9g8
Severity MODERATE
CVSS v3.1 Base Score 6.1
CWE Classification CWE-116: Improper Encoding or Escaping of Output
Affected Product @swc/html
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 6.1

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction Required (UI:R)
Scope Changed (S:C)
Confidentiality Low (C:L)
Integrity Low (I:L)
Availability None (A:N)

How to Fix CVE-2026-72925

To remediate this vulnerability, upgrade all affected @swc/html dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

@swc/html fixed: 1.15.47-nightly-20260729.1 
npm install @swc/html@1.15.47-nightly-20260729.1
swc_html_minifier fixed: 59.0.0 
Upgrade swc_html_minifier to 59.0.0
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

npm ls @swc/html

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2026-72925, inspect your project dependencies using npm:

npm ls @swc/html

Analyze the terminal output to locate any version of @swc/html in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.15.47-nightly-20260729.1), your application is affected.

Note: The npm ls @swc/html command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-116: Improper Encoding or Escaping of Output, where 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. In @swc/html, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

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

CVE-2026-72925 Affected @swc/html Versions

2 component(s)
Fixed Versions:
1.15.47-nightly-20260729.159.0.0
Product / Package Ecosystem Affected Versions Fixed Version
@swc/html
npm/@swc/html
npm
< 1.15.47-nightly-20260729.1
1.15.47-nightly-20260729.1
swc_html_minifier
 crates.io
< 59.0.0
59.0.0

References

GitHub Advisory / Wiki ADVISORY
https://github.com/swc-project/swc/security/advisories/GHSA-5qr2-v392-m9g8
NVD — CVE-2026-72925 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-72925
@swc/html Source Repository REPOSITORY
https://github.com/swc-project/swc/pull/12080
Security Fix Commit FIX COMMIT
https://github.com/swc-project/swc/commit/e1877b44bdac8abc9fd51e984d584f40f6999832
@swc/html Source Repository REPOSITORY
https://github.com/swc-project/swc
@swc/html Release RELEASE
https://github.com/swc-project/swc/releases/tag/v1.15.47
@swc/html Release RELEASE
https://github.com/swc-project/swc/releases/tag/v1.15.47-nightly-20260729.1

Frequently Asked Questions

What is CVE-2026-72925?
CVE-2026-72925 is a security vulnerability in @swc/html involving SWC HTML minifier may allow script element breakout when minifying embedded JSON under CWE-116: Improper Encoding or Escaping of Output.
Which @swc/html versions are affected?
Affected versions include releases prior to 1.15.47-nightly-20260729.1, 59.0.0 across affected packages: @swc/html, swc_html_minifier.
What version fixes CVE-2026-72925?
Upgrading to 1.15.47-nightly-20260729.1, 59.0.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is @swc/html affected?
Yes, @swc/html is affected in releases prior to 1.15.47-nightly-20260729.1. Upgrade your dependency to 1.15.47-nightly-20260729.1 or later.
Is swc_html_minifier affected?
Yes, swc_html_minifier is affected in releases prior to 59.0.0. Upgrade your dependency to 59.0.0 or later.
What is the CVSS score of CVE-2026-72925?
CVE-2026-72925 has a CVSS v3.1 base score of 6.1 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.
What CWE is associated with CVE-2026-72925?
CVE-2026-72925 is classified under CWE-116: Improper Encoding or Escaping of Output (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.).
How can I check npm dependencies for CVE-2026-72925?
Run the dependency tree command: 'npm ls @swc/html'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-5qr2-v392-m9g8",
  "modified" : "2026-09-08T17:58:00Z",
  "published" : "2026-09-08T17:58:00Z",
  "aliases" : [ "CVE-2026-72925" ],
  "summary" : "SWC HTML minifier may allow script element breakout when minifying embedded JSON",
  "details" : "## Impact\n\n`@swc/html` minifies JSON contained in `script` elements such as\n`application/json` and `application/ld+json` by parsing and serializing the\nJSON value.\n\nBefore the patched versions, JSON serialization could convert escaped\nless-than signs such as `\\u003C` into literal `<` characters. If the JSON\ncontained an escaped `</script>` sequence, the generated HTML could terminate\nthe containing script element early because HTML tokenization occurs before\nthe JSON is consumed.\n\nApplications that minify HTML containing attacker-controlled JSON data could\ntherefore transform inert data into active markup. A crafted payload could\nexecute script in the origin of the generated page.\n\n## Patches\n\nThe issue is fixed in:\n\n- `@swc/html` 1.15.47\n- `swc_html_minifier` 59.0.0\n\nThe minifier now re-escapes less-than signs after JSON serialization, preserving\nthe script element boundary.\n\n## Workarounds\n\nUsers who cannot upgrade can disable JSON minification with:\n\n```js\nawait minify(html, {\n  minifyJson: false,\n});",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "@swc/html"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.15.47-nightly-20260729.1"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "crates.io",
      "name" : "swc_html_minifier"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "59.0.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/swc-project/swc/security/advisories/GHSA-5qr2-v392-m9g8"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-72925"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/swc-project/swc/pull/12080"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/swc-project/swc/commit/e1877b44bdac8abc9fd51e984d584f40f6999832"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/swc-project/swc"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/swc-project/swc/releases/tag/v1.15.47"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/swc-project/swc/releases/tag/v1.15.47-nightly-20260729.1"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-116", "CWE-79" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-09-08T17:58:00Z",
    "nvd_published_at" : "2026-08-11T15:17:38Z"
  }
}