CVE-2021-47764Public exploit

Application crash via oversized GUI field input

Published Jan 15, 2026 · Updated Jan 15, 2026

Denial of service in Celestial Software AbsoluteTelnet 11.24 allows local users to crash the application via oversized GUI input. The DialUp phone and license-name handlers accept a pasted 1,000-character string without sufficient bounds enforcement and terminate when the associated action is submitted. Exploitation requires interactive access to the Windows client and interrupts only that application process.

CVSS severity6.7
Medium
EPSS probability0.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Celestial Software AbsoluteTelnet 11.24 allows local users to crash the application via oversized GUI input. The DialUp phone and license-name handlers accept a pasted 1,000-character string without sufficient bounds enforcement and terminate when the associated action is submitted. Exploitation requires interactive access to the Windows client and interrupts only that application process.

The record

CVE
CVE-2021-47764
Published
Jan 15, 2026
Updated
Jan 15, 2026
Vendor
Celestial Software
Product
AbsoluteTelnet
Classifications
CWE-787, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 15, 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=11.24

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Celestial Software · AbsoluteTelnetversion=11.24

Published CVSS scores

5.5VulnCheckCVSS:3.1/AV:L/AC:L/PR:L/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

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)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1499Endpoint Denial of Service

Public exploit references

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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