How severe is GHSA-v8w9-8mx6-g223?

GHSA-v8w9-8mx6-g223 has a CVSS score of 4.8/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by GHSA-v8w9-8mx6-g223?

GHSA-v8w9-8mx6-g223 affects the following packages: hono (npm). Ecosystems affected: npm.

How do I fix GHSA-v8w9-8mx6-g223?

Update hono to 4.12.7 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-v8w9-8mx6-g223 is resolved across your whole dependency graph.

How do I detect GHSA-v8w9-8mx6-g223 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for hono. 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-v8w9-8mx6-g223 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-v8w9-8mx6-g223?

O3 pinpoints whether GHSA-v8w9-8mx6-g223 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-v8w9-8mx6-g223 actively exploited in the wild?

No public exploit code has been indexed for GHSA-v8w9-8mx6-g223 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-v8w9-8mx6-g223 published, and has it been updated?

GHSA-v8w9-8mx6-g223 was published on March 11, 2026 and was last updated on March 13, 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-v8w9-8mx6-g223

MEDIUM

Hono vulnerable to Prototype Pollution possible through __proto__ key allowed in parseBody({ dot: true })

Published

Mar 11, 2026

Updated

Mar 13, 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.

hononpm

47.6Mdownloads / week

Description

Summary

When using parseBody({ dot: true }) in HonoRequest, specially crafted form field names such as __proto__.x could create objects containing a __proto__ property.

If the parsed result is later merged into regular JavaScript objects using unsafe merge patterns, this may lead to prototype pollution in the target object.

Details

The parseBody({ dot: true }) feature supports dot notation to construct nested objects from form field names.

In previous versions, the __proto__ path segment was not filtered. As a result, specially crafted keys such as __proto__.x could produce objects containing __proto__ properties.

While this behavior does not directly modify Object.prototype within Hono itself, it may become exploitable if the parsed result is later merged into regular JavaScript objects using unsafe merge patterns.

Impact

Applications that merge parsed form data into regular objects using unsafe patterns (for example recursive deep merge utilities) may become vulnerable to prototype pollution.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`hono`	all versions	4.12.7

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for hono. 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 hono to 4.12.7 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-v8w9-8mx6-g223 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-v8w9-8mx6-g223 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-v8w9-8mx6-g223. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

## Summary When using `parseBody({ dot: true })` in HonoRequest, specially crafted form field names such as `__proto__.x` could create objects containing a `__proto__` property. If the parsed result is later merged into regular JavaScript objects using unsafe merge patterns, this may lead to prototype pollution in the target object. ## Details The `parseBody({ dot: true })` feature supports dot notation to construct nested objects from form field names. In previous versions, the `__proto__` path segment was not filtered. As a result, specially crafted keys such as `__proto__.x` could prod

O3 Security · Impact-Aware SCA

Is GHSA-v8w9-8mx6-g223 in your dependencies?

O3 detects GHSA-v8w9-8mx6-g223 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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