# CVE-2026-56763: Hono prototype pollution in parseBody with dot option enabled

Source: https://junglewise.ai/threats/cve-2026-56763-hono-prototype-pollution-in-parsebody-with-dot-option-enabled  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-11. Updated: 2026-07-11  
License: CC BY 4.0 with a link back

CVE-2026-56763 · Severity: medium · CVSS 4.8 · Published 2026-07-11

Hono is a popular web framework used to build fast web applications. A vulnerability in how it handles form data allows attackers to submit specially crafted input that can interfere with the application's internal logic. If the application then combines this data with other internal objects, it could lead to unauthorized data access or changes to how the application behaves.

Technologies: [hono (npm)](https://junglewise.ai/threats/technologies/hono). Vendors: [npm](https://junglewise.ai/threats/vendors/npm).

## Quick answers

**Is CVE-2026-56763 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-56763 being exploited in the wild.

**How severe is CVE-2026-56763?** Medium severity, with a CVSS score of 4.8, published 11 July 2026.

**Which products and versions are affected?** hono (npm) < 4.12.7, SEMVER:introduced=0,fixed=4.12.7.

**Is there a fix for CVE-2026-56763?** Yes. hono (npm): upgrade to 4.12.7 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-56763 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-56763?** Check whether you run hono (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- hono (npm): upgrade to 4.12.7 or later

  ```sh
  npm install hono@4.12.7
  ```


## Technical details

A prototype pollution vulnerability exists in Hono's HonoRequest.parseBody() method when the { dot: true } option is enabled. The parser fails to filter the '__proto__' path segment in form field names, allowing an attacker to construct objects containing __proto__ properties. While Hono does not modify the global Object.prototype directly, if the resulting parsed object is subsequently merged into other JavaScript objects using unsafe recursive deep merge patterns, an attacker can achieve prototype pollution. This can lead to modification of object behavior or potential bypass of security checks. The issue is fixed in version 4.12.7.

## Affected products

- Hono Hono < 4.12.7

## Identifiers

- CVE-2026-56763
- GHSA-v8w9-8mx6-g223

## Timeline

- 2026-03-10: advisory: GitHub Security Advisory published
- 2026-07-11: disclosed: NVD publication date
- 2026-07-11: patched: Fix confirmed in version 4.12.7

## References

- [https://github.com/honojs/hono/security/advisories/GHSA-v8w9-8mx6-g223](https://github.com/honojs/hono/security/advisories/GHSA-v8w9-8mx6-g223)
- [https://www.vulncheck.com/advisories/hono-prototype-pollution-via-proto-key-in-parsebody-with-dot-option](https://www.vulncheck.com/advisories/hono-prototype-pollution-via-proto-key-in-parsebody-with-dot-option)

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