How severe is GHSA-mcm9-63f2-9j32?

No CVSS score has been assigned to GHSA-mcm9-63f2-9j32 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-mcm9-63f2-9j32?

GHSA-mcm9-63f2-9j32 affects the following packages: devalue (npm). Ecosystems affected: npm.

How do I fix GHSA-mcm9-63f2-9j32?

Update devalue to 5.9.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-mcm9-63f2-9j32 is resolved across your whole dependency graph.

How do I detect GHSA-mcm9-63f2-9j32 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for devalue, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate GHSA-mcm9-63f2-9j32 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is GHSA-mcm9-63f2-9j32 actively exploited in the wild?

No public exploit code has been indexed for GHSA-mcm9-63f2-9j32 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

When was GHSA-mcm9-63f2-9j32 published, and has it been updated?

GHSA-mcm9-63f2-9j32 was published on October 1, 2026 and was last updated on October 1, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦 npm

Not in CISA KEV

devalue: Repeated primitive strings cause quadratic expansion in unevalGHSA-mcm9-63f2-9j32

Fix: sveltejs/devalue@84f6f67

GHSA-mcm9-63f2-9j32 is a security vulnerability in devalue. A fix is available for devalue — see the affected versions and patch details below.

Published

Oct 1, 2026

Updated

Oct 1, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 1, 2026 · OSV.dev, FIRST.org (EPSS)

Real-World Exposure

1 pkg affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

377other npm packages depend on this — each one inherits the vulnerability until it's patched upstream

devaluenpm

11.0Mdownloads / week

Description

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

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`devalue`	all versions	5.9.3`npm install devalue@5.9.3`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for devalue, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update devalue to 5.9.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-mcm9-63f2-9j32 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

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.

O3 Security · Impact-Aware SCA

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