CVE-2026-84364Network attack vectorHinoki check available

Service interruption via unbounded dot-notation expansion

Published Sep 1, 2026 · Updated Sep 2, 2026

Denial of service in Hono before 4.13.5 allows remote attackers to terminate server processes via crafted dotted form fields. The parseBody() dot option splits each form key at every period and creates intermediate objects without depth or aggregate-count limits. Exploitation requires an endpoint configured with dot-notation parsing; concurrent requests can exhaust the JavaScript heap and leave service unavailable until restart.

CVSS severity5.3
Medium
EPSS probability0.39%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Denial of service in Hono before 4.13.5 allows remote attackers to terminate server processes via crafted dotted form fields. The parseBody() dot option splits each form key at every period and creates intermediate objects without depth or aggregate-count limits. Exploitation requires an endpoint configured with dot-notation parsing; concurrent requests can exhaust the JavaScript heap and leave service unavailable until restart.

The record

CVE
CVE-2026-84364
Published
Sep 1, 2026
Updated
Sep 2, 2026
Vendor
Hono
Product
Hono
Classifications
CWE-400, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 1, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 2, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 4.13.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Hono · Honoversion=< 4.13.5

Published CVSS scores

5.3GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-400Uncontrolled Resource Consumption
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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