MobaXterm: Unquoted Search Path or Element
CVE-2026-25866 is a high-severity unquoted search path or element vulnerability in MobaXterm from Mobatek, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists version 26.1 as the first without the flaw, so updating MobaXterm to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.15% 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 MobaXterm to 26.1 or a later version.
- Read the advisory on mobaxterm.mobatek.net for workarounds and exact fixed builds.
Affected products and versions
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
- LocalThe attacker needs local access or must trick a user into running something.
- 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:L/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 | 8.5 | High | CNA (vulncheck.com) |
| CVSS 3.1 | 7.8 | High | CNA (vulncheck.com) |
Official description
MobaXterm versions prior to 26.1 contain an uncontrolled search path element vulnerability. The application calls WinExec to execute Notepad++ without a fully qualified executable path when opening remote files. An attacker can exploit the search path behavior by placing a malicious executable earlier in the search order, resulting in arbitrary code execution in the context of the affected user.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Unquoted Search Path or Element
The product uses a search path that contains an unquoted element, in which the element contains whitespace or other separators. This can cause the product to access resources in a parent path.
How developers prevent this class of flaw
- Properly quote the full search path before executing a program on the system.
- Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174). Such errors could be used to bypass allowlist validation schemes by introducing dangerous inputs after they have been checked.
More Unquoted Search Path or Element vulnerabilities (CWE-428)
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
Third-party and government advisories
- vulncheck.com/advisories/mobaxterm-notepad-unquoted-service-pathThird Party Advisory
Other vulnerabilities in MobaXterm
- 8.5 High severity
- 9.1 Critical severity
- 8.1 High severity
Recent Unquoted Search Path or Element vulnerabilities
- 8.5 High severity
- 8.4 High severity
- 8.4 High severity
- 7.8 High severity
- 8.4 High severity
- 8.4 High severity
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