CVE-2026-56763

MEDIUM
MEDIUM Priority: 0.02 BB Relevance: 63/100
Published: 2026-07-11 Modified: 2026-10-25 First seen: 2026-10-29 Status: active

Attack Surface

Network No Auth No Interaction

CVSS Vector Breakdown

AV: Network
AC: High
PR: None
UI: None
S: X
AT: Present
VC: Low
VI: Low
VA: None

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.

Weakness Classification (1)

Bug Bounty Relevance

63 / 100
✓ Network accessible
✓ No authentication
✓ No user interaction

CVSS Score

6.3 / 10.0 v4.0
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS — Exploitation Probability

0.27%
Raw Score 0.002730
Percentile 19.7%
Date 2026-10-29

EPSS Trend

2026-10-29
0.00273
2026-10-28
0.00273

Intelligence Sources

nvd ref →