AbsoluteTelnet 11.12 - 'SSH2/username' Denial of Service

published 2026-02-06 9 mo ago modified 2026-10-01 38 d ago also EUVD-2020-31118

cvss: 6.2; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.2%; EPSS 0.2% chance of exploitation in 30 days, percentile 14%
public exploits: 0; none known

AbsoluteTelnet 11.12 contains a denial of service vulnerability in the SSH2 username input field that allows local attackers to crash the application. Attackers can overwrite the username field with a 1000-byte buffer, causing the application to become unresponsive and terminate.

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: partial
Assessed: 8 mo ago (2026-02-17)

Exploit prediction

0.24% chance of exploitation in the next 30 days, higher than 14% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

exploit-db.com https://www.exploit-db.com/exploits/48010 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	4.0	6.9	CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CNA	3.1	6.2	CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA	4.0	6.9	CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD	3.1	5.5	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

Celestial Software AbsoluteTelnet

Classification

Weakness

CWE-120 Buffer Copy without Checking Size of Input

References

exploit-db.com /exploits/48010
exploit, third-party-advisory, vdb-entry
celestialsoftware.net /
product
vulncheck.com /advisories/absolutetelnet-sshusername-denial-of-service
third-party-advisory, broken-link

Sources

CVE List CVE-2020-37166
NVD CVE-2020-37166

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary