F5 BIG-IP tmsh arp/ndp PrivEsc Exposing Adjacent Net Info
CVE-2026-42937 Published on May 13, 2026
iControl REST and tmsh vulnerability
Incorrect permission assignment vulnerabilities exist in BIG-IP and BIG-IQ TMOS Shell (tmsh) arp and ndp commands, and in BIG-IP iControl REST. These vulnerabilities may allow an authenticated attacker to view adjacent network information.
Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
Vulnerability Analysis
CVE-2026-42937 can be exploited with network access, and requires small amount of user privileges. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have a high impact on confidentiality, with no impact on integrity and availability.
Weakness Type
Incorrect Permission Assignment for Critical Resource
The product specifies permissions for a security-critical resource in a way that allows that resource to be read or modified by unintended actors. When a resource is given a permissions setting that provides access to a wider range of actors than required, it could lead to the exposure of sensitive information, or the modification of that resource by unintended parties. This is especially dangerous when the resource is related to program configuration, execution or sensitive user data.
Products Associated with CVE-2026-42937
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Affected Versions
F5 BIG-IP:- Version 21.1.0 and below * is unaffected.
- Version 21.0.0 and below 21.0.0.2 is affected.
- Version 17.5.0 and below 17.5.1.6 is affected.
- Version 17.1.0 and below 17.1.3.2 is affected.
- Version 16.1.0 and below * is affected.
- Version 8.4.0 and below * is affected.