ThinLinc: Authentication Bypass by Spoofing
CVE-2026-119744 is a high-severity authentication bypass by spoofing vulnerability in ThinLinc from Cendio, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. The record lists versions 4.15.1, 4.16.1, 4.17.1 as the first without the flaw, so updating ThinLinc to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.44% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update ThinLinc to 4.15.1 or 4.16.1 or 4.17.1 or 4.18.1, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Cendio | ThinLinc | 4.1.0 up to, but not including, 4.15.1; 4.16.0 up to, but not including, 4.16.1; 4.17.0 up to, but not including, 4.17.1; 4.18.0 up to, but not including, 4.18.1; 4.19.0 up to, but not including, 4.19.1; 4.20.0 up to, but not including, 4.20.1 | 4.15.1, 4.16.1, 4.17.1, 4.18.1, 4.19.1, 4.20.1 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by CNA (vulncheck.com).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 7.7 | High | CNA (vulncheck.com) |
| CVSS 3.1 | 8.8 | High | CNA (vulncheck.com) |
Official description
Cendio ThinLinc contains an improper authentication vulnerability in its browser-based web client (tlwebaccess) that allows an authenticated attacker to impersonate any other user, including root, by exploiting flaws in multi-step authentication flows such as one-time passwords, login banners, or expired password prompts. Attackers can leverage this authentication bypass during the multi-step login process to gain unauthorized access to other user accounts, including administrative privileges, in versions from 4.1.0 through 4.20.0.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Authentication Bypass by Spoofing
This attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks.
More Authentication Bypass by Spoofing vulnerabilities (CWE-290)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other references
Recent Authentication Bypass by Spoofing vulnerabilities
- 9.1 Critical severity
- 8.3 High severity
- 9.8 Critical severity
- 8.1 High severity
- 7.7 High severity
- 9.3 Critical severity
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