GHSA-mcm9-63f2-9j32: devalue Repeated Primitive Strings Cause Quadratic Vulnerability

HIGH
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CWE-409 CWE-400
Published
Advisory Summary

GHSA-mcm9-63f2-9j32 is a HIGH repeated primitive strings cause quadratic vulnerability (CWE-409: Improper Handling of Highly Compressed Data (Data Amplification)) affecting devalue libraries in the npm ecosystem. The issue involves repeated primitive strings cause quadratic expansion in uneval. Remediation is available by upgrading affected packages to version 5.9.3.

GHSA-mcm9-63f2-9j32 at a Glance

CVE Identifier N/A
GHSA Identifier GHSA-mcm9-63f2-9j32
Severity HIGH
CVSS v3.1 Base Score N/A
CWE Classification CWE-409: Improper Handling of Highly Compressed Data (Data Amplification)
Affected Product devalue
Package Ecosystem npm
Published Date
Last Updated

How to Fix GHSA-mcm9-63f2-9j32

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

devalue fixed: 5.9.3 
npm install devalue@5.9.3
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 devalue

How to Check if You Are Affected

To determine whether your Node.js application is affected by GHSA-mcm9-63f2-9j32, inspect your project dependencies using npm:

npm ls devalue

Analyze the terminal output to locate any version of devalue in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 5.9.3), your application is affected.

Note: The npm ls devalue 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-409: Improper Handling of Highly Compressed Data (Data Amplification), where the product does not handle or incorrectly handles a compressed input with a very high compression ratio that produces a large output. In devalue, 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

Under very constrained circumstances, data that was `parse`d and then passed to `uneval` could turn a small payload into a very large serialized string.

GHSA-mcm9-63f2-9j32 Affected devalue Versions

1 component(s)
Fixed Versions:
5.9.3
Product / Package Ecosystem Affected Versions Fixed Version
devalue
npm/devalue
npm
< 5.9.3
5.9.3

References

GitHub Advisory / Wiki ADVISORY
https://github.com/sveltejs/devalue/security/advisories/GHSA-mcm9-63f2-9j32
Security Fix Commit FIX COMMIT
https://github.com/sveltejs/devalue/commit/84f6f67999104e36940f744bec0443536de1b463
devalue Source Repository REPOSITORY
https://github.com/sveltejs/devalue
devalue Release RELEASE
https://github.com/sveltejs/devalue/releases/tag/v5.9.3

Frequently Asked Questions

What is GHSA-mcm9-63f2-9j32?
GHSA-mcm9-63f2-9j32 is a security vulnerability in devalue involving Repeated primitive strings cause quadratic expansion in uneval under CWE-409: Improper Handling of Highly Compressed Data (Data Amplification).
Which devalue versions are affected?
Affected versions include releases prior to 5.9.3 across affected packages: devalue.
What version fixes GHSA-mcm9-63f2-9j32?
Upgrading to 5.9.3 (or the latest patched release for your respective branch) resolves the vulnerability.
Is devalue affected?
Yes, devalue is affected in releases prior to 5.9.3. Upgrade your dependency to 5.9.3 or later.
What CWE is associated with GHSA-mcm9-63f2-9j32?
GHSA-mcm9-63f2-9j32 is classified under CWE-409: Improper Handling of Highly Compressed Data (Data Amplification) (The product does not handle or incorrectly handles a compressed input with a very high compression ratio that produces a large output.).
How can I check npm dependencies for GHSA-mcm9-63f2-9j32?
Run the dependency tree command: 'npm ls devalue'. 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-mcm9-63f2-9j32",
  "modified" : "2026-10-01T15:17:29Z",
  "published" : "2026-10-01T15:17:29Z",
  "aliases" : [ ],
  "summary" : "devalue: Repeated primitive strings cause quadratic expansion in uneval",
  "details" : "Under very constrained circumstances, data that was `parse`d and then passed to `uneval` could turn a small payload into a very large serialized string.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "devalue"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "5.9.3"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 5.9.2"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/sveltejs/devalue/security/advisories/GHSA-mcm9-63f2-9j32"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/sveltejs/devalue/commit/84f6f67999104e36940f744bec0443536de1b463"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/sveltejs/devalue"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/sveltejs/devalue/releases/tag/v5.9.3"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-400", "CWE-409" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-10-01T15:17:29Z",
    "nvd_published_at" : null
  }
}