CVE-2020-11939Network attack vector

Remote code execution via KEXINIT offset truncation

Published Apr 23, 2020 · Updated Aug 4, 2024

Heap overflow in the SSH dissector of ntop nDPI 3.0 through 3.2 allows remote attackers to execute code via crafted KEXINIT traffic. concat_hash_string truncates attacker-controlled 32-bit length arithmetic into a 16-bit packet offset, bypassing bounds checks before repeated copies advance an unchecked destination offset beyond the allocated heap buffer. Exploitation requires a network inspection stack linked to nDPI to analyze the crafted traffic, and successful corruption grants code execution in that stack's process.

CVSS severity9.8
Critical
EPSS probability3.30%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap overflow in the SSH dissector of ntop nDPI 3.0 through 3.2 allows remote attackers to execute code via crafted KEXINIT traffic. concat_hash_string truncates attacker-controlled 32-bit length arithmetic into a 16-bit packet offset, bypassing bounds checks before repeated copies advance an unchecked destination offset beyond the allocated heap buffer. Exploitation requires a network inspection stack linked to nDPI to analyze the crafted traffic, and successful corruption grants code execution in that stack's process.

The record

CVE
CVE-2020-11939
Published
Apr 23, 2020
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-190, CWE-787
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 23, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5NVDAV:N/AC:L/Au:N/C:P/I:P/A:P

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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-190Integer Overflow or Wraparound
CWE-787Out-of-bounds Write

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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