How severe is GHSA-866w-xmhq-wj7x?

GHSA-866w-xmhq-wj7x has a CVSS score of 4.3/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by GHSA-866w-xmhq-wj7x?

GHSA-866w-xmhq-wj7x affects the following packages: @sveltejs/kit (npm). Ecosystems affected: npm.

How do I fix GHSA-866w-xmhq-wj7x?

Update @sveltejs/kit to 2.69.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-866w-xmhq-wj7x is resolved across your whole dependency graph.

How do I detect GHSA-866w-xmhq-wj7x in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @sveltejs/kit. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate GHSA-866w-xmhq-wj7x 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.

How does O3 Security protect against GHSA-866w-xmhq-wj7x?

O3 pinpoints whether GHSA-866w-xmhq-wj7x is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is GHSA-866w-xmhq-wj7x actively exploited in the wild?

No public exploit code has been indexed for GHSA-866w-xmhq-wj7x 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-866w-xmhq-wj7x published, and has it been updated?

GHSA-866w-xmhq-wj7x was published on July 24, 2026 and was last updated on July 24, 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

GHSA-866w-xmhq-wj7x

MEDIUM

SvelteKit: Prototype pollution in file input deletion path in remote-function forms

Published

Jul 24, 2026

Updated

Jul 24, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Blast Radius

1 pkg affected

Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.

@sveltejs/kitnpm

2.3Mdownloads / week

Description

If you use remote form functions, have an input field of type file, and accept arbitrary user-controlled path names for the field, then you are vulnerable to a prototype pollution attack where the attacker can remove e.g. methods on the prototype.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`@sveltejs/kit`	all versions	2.69.1

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @sveltejs/kit. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update @sveltejs/kit to 2.69.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-866w-xmhq-wj7x 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.
How O3 protects you
O3 pinpoints whether GHSA-866w-xmhq-wj7x is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-866w-xmhq-wj7x. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

If you use remote form functions, have an input field of type `file`, and accept arbitrary user-controlled path names for the field, then you are vulnerable to a prototype pollution attack where the attacker can remove e.g. methods on the prototype.

O3 Security · Impact-Aware SCA

Is GHSA-866w-xmhq-wj7x in your dependencies?

O3 detects GHSA-866w-xmhq-wj7x across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works