Security readout for executives and security teams
Plain-English summary
CVE-2026-42058 affects F5 BIG-IP iControl REST. An authenticated attacker can send undisclosed requests that reveal local BIG-IP user account names. This is not a system takeover by itself, but exposed usernames can support later password attacks, phishing, or privilege escalation attempts.
Executive priority
Treat as a medium-priority exposure management item. It does not indicate unauthenticated compromise, but leaked administrator or local account names can lower the barrier for follow-on attacks against critical traffic-management infrastructure.
Technical view
The issue is an information disclosure vulnerability in BIG-IP iControl REST, mapped to CWE-732. CVSS 4.0 score is 5.3, with network access, low attack complexity, low privileges required, and no user interaction. Impact is limited to confidentiality of vulnerable component data.
Likely exposure
Organizations running affected BIG-IP versions 21.1.0, 21.0.0, 17.5.0, 17.1.0, or 16.1.0 may be exposed if iControl REST is reachable by authenticated users. End-of-Technical-Support versions were not evaluated.
Exploitation context
The sources do not report active exploitation, and this CVE is not listed as KEV in the provided data. Exploitation requires authentication and targets account-name disclosure through iControl REST. The exact request details are undisclosed in the provided sources.
Researcher notes
Evidence is limited to the CVE record and F5 advisory reference. The vulnerability requires low privileges and leaks local user account names. No exploit details, active exploitation evidence, or EoTS evaluation data are provided in the source bundle.
Mitigation direction
- Review F5 advisory K000160903 for fixed versions, hotfixes, and official guidance.
- Restrict iControl REST access to trusted administrative networks and users.
- Audit BIG-IP local accounts for unnecessary or stale users.
- Prioritize remediation where iControl REST is reachable beyond tightly managed administration paths.
Validation and detection
- Identify BIG-IP systems and record software versions.
- Confirm whether listed affected versions are present.
- Verify iControl REST exposure and who can authenticate to it.
- Check vendor advisory K000160903 for applicability and remediation status.
- Review logs for unusual authenticated iControl REST activity.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-732: Authorization and privilege behavior lookup
Authorization weaknesses can support privilege escalation and valid-account review, depending on exploit path. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2026-42058 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 5.3 (4.0)
- Known Exploited
- No
- Published
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
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
SSVC decision data
CVSS vector scores
2 official scoresWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
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——f5CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N2.81.4f5Vulnerability scoring details
Base CVSS 4.0 score
5.3MediumVector: 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
Base CVSS 3.1 score
4.3MediumVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://my.f5.com/manage/s/article/K000160903CVE reference, f5 · vendor-advisory, patch
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Incorrect Permission Assignment for Critical Resource
Incorrect Permission Assignment for Critical Resource represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.