CVE-2025-59139Network attack vector

Service interruption via conflicting length headers

Published Sep 12, 2025 · Updated Sep 12, 2025

Resource exhaustion in Hono before 4.9.7 allows remote attackers to interrupt services via oversized chunked HTTP requests. The bodyLimit middleware trusts Content-Length even when Transfer-Encoding is present, so it skips measuring the actual chunked body. Exploitation requires an application using bodyLimit and a runtime or proxy that forwards conflicting headers; excessive processing can exhaust memory or CPU.

CVSS severity5.3
Medium
EPSS probability0.45%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource exhaustion in Hono before 4.9.7 allows remote attackers to interrupt services via oversized chunked HTTP requests. The bodyLimit middleware trusts Content-Length even when Transfer-Encoding is present, so it skips measuring the actual chunked body. Exploitation requires an application using bodyLimit and a runtime or proxy that forwards conflicting headers; excessive processing can exhaust memory or CPU.

The record

CVE
CVE-2025-59139
Published
Sep 12, 2025
Updated
Sep 12, 2025
Vendor
Hono
Product
Hono
Classifications
CWE-770, CWE-400, T1499.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 12, 2025CVE publishedPublication date reported by the CVE source.
  2. Sep 12, 2025Record 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=< 4.9.7

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Hono · Honoversion=< 4.9.7

Published CVSS scores

5.3GitHub, Inc.CVSS: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-770Allocation of Resources Without Limits or Throttling
CWE-400Uncontrolled Resource Consumption
T1499.003Application Exhaustion Flood

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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