CVE-2020-37165Public exploit

Client crash via oversized license name

Published Feb 6, 2026 · Updated Feb 6, 2026

Classic buffer overflow in AbsoluteTelnet 11.12 allows local users to crash the Windows client through an oversized license name. The Enter License Key dialog copies a 2,500-character value from the License Name field without enforcing the destination buffer's size. Reaching the flaw requires interactive access to the running client and pasting the payload; the documented consequence is termination of that client process.

CVSS severity6.7
Medium
EPSS probability0.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Classic buffer overflow in AbsoluteTelnet 11.12 allows local users to crash the Windows client through an oversized license name. The Enter License Key dialog copies a 2,500-character value from the License Name field without enforcing the destination buffer's size. Reaching the flaw requires interactive access to the running client and pasting the payload; the documented consequence is termination of that client process.

The record

CVE
CVE-2020-37165
Published
Feb 6, 2026
Updated
Feb 6, 2026
Vendor
Celestial Software
Product
AbsoluteTelnet
Classifications
CWE-120, T1499.004
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 6, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 6, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=11.12

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Celestial Software · AbsoluteTelnetversion=11.12

Published CVSS scores

6.2VulnCheckCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
6.7VulnCheckCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
5.5NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

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)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
T1499.004Application or System Exploitation

Public exploit references

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

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo