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Medium 4.8Published Jul 11, 2026

CVE-2026-56763Hono - Prototype Pollution via __proto__ Key in parseBody with dot Option

Updated under an hour ago ()

Does this affect you?

It affects Hono. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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
4.8 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
Weakness (CWE)
CWE-1321
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
VulnCheck
NVD analysis
Deferred
Record last updated
Jul 14, 2026
First seen by InfoSec Signals
Oct 9, 2026

Affected products

Affected products
Hono Hono
hono:hono (from the name)
before 4.12.7; 4.12.7 not affected
CNA record

References

References

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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