6.3

CVE-2026-56763: hono Prototype Pollution

CVSS: 6.3v4.0MediumDeferred
AliasesCGA-2956-xqwv-cw6vCGA-xpqx-pgp7-86wwGHSA-v8w9-8mx6-g223
Published 11-07-2026Last modified 14-07-2026
Open JSON

Vulnerability summary

CVE-2026-56763 is a medium (CVSS 6.3) Prototype Pollution vulnerability in hono. EPSS estimates a 0.27% chance of exploitation in the next 30 days, higher than 18.5% of scored vulnerabilities.

Overall risk
25/100
0100
Medium · default modelHow is this calculated?
CVSS score
6.3/10
010
Medium · v4.0 (CVE.org)
EPSS score
0.27%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 1 · Downstream 0
GHSA-3WCJ-GJVF-FVCH

Timeline

  1. 11-07-2026
    PublishedVulnerability first disclosed.
  2. 14-07-2026
    Last modifiedVulnerability information updated.

Description

Hono before 4.12.7 allows __proto__ key in parseBody with dot option enabled, permitting specially crafted form field names to create objects with __proto__ properties. When parsed results are merged into regular JavaScript objects using unsafe merge patterns, attackers can exploit this to achieve prototype pollution and modify object behavior.

CVSS metrics

7 scores · 5 sources · 2 versions

EPSS trend

Probability

0.27%

Chance of exploitation in the next 30 days

Percentile

19%

Versus all other CVEs

30-day change

0.00 pp

From 0.27% on 21-09-2026

21-09-202621-10-2026
EPSS score
0.27%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Chainguard18 products
  • honoAll versions (No fix recorded)
  • hono-adapter-mqttAll versions (No fix recorded)
  • hono-cliAll versions (No fix recorded)
  • hono-compatAll versions (No fix recorded)
  • hono-service-authAll versions (No fix recorded)
Hono1 product
Npm1 product
  • hono< 4.12.7
Wolfi1 product
  • langfuse-3-worker< 3.158.0-r0

4 vendors · 21 products

References

6 links