CVE-2026-42058
F5 Big-Ip Access Policy Manager 17.1.0 – 17.1.3
Raw vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/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:XSummary
CVE-2026-42058 is a medium-severity Incorrect Permission Assignment for Critical Resource (CWE-732) vulnerability in F5 Big-Ip Access Policy Manager. Its CVSS base score is 5.3 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Local Account (T1087.001); ranked at the 9th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to AC-3 (Access Enforcement) and AC-6 (Least Privilege) — see the control section below for these in your framework.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-29993
Vulnerability Data
An authenticated attacker's undisclosed requests to BIG-IP iControl REST can lead to an information leak of BIG-IP local user account names. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Direct information disclosure of local account names via authenticated API access enables local account discovery.
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
Mitigating Controls (NIST 800-53 r5) AI
Directly enforces access restrictions on the iControl REST interface so that authenticated users cannot retrieve local account names via improper permission assignments.
Requires least-privilege permission assignments on critical resources (CWE-732), preventing the excessive rights that allow the information leak.
Enforces information-flow rules that can block unauthorized disclosure of account-name data through the REST API.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
By requiring owners to determine and document the exact permissions needed for each asset, the control reduces the likelihood that default or overly permissive file and resource permissions will be left in place.
Documented provisioning and revocation procedures reduce the chance that critical resources retain overly permissive default or leftover permissions after personnel changes.
Documented authorization, expiry rules, and audit logging of privileged accounts make it harder for critical resources to retain overly permissive or stale permission assignments.
Requiring explicit configuration of access controls and permissions for files, applications and services counters the assignment of overly permissive default or incorrect file-system rights.
Enforcing differentiated permissions on the source-code repository and program listings stops the assignment of overly broad default or inherited permissions to critical resources.
By defining and enforcing secure permission settings in configuration templates, the control reduces the likelihood that critical resources receive incorrect permission assignments.