CVE-2026-42937Network attack vector

Adjacent network disclosure via overpermissive management interfaces

Published May 13, 2026 · Updated May 13, 2026

Incorrect permission assignment in F5 BIG-IP and BIG-IQ allows attackers with authenticated access to view adjacent network information. The tmsh arp and ndp commands on both products, plus BIG-IP iControl REST, expose neighbor data under permissions broader than intended. BIG-IP is network-reachable with low privileges, while BIG-IQ requires local low-privileged access; the published impact is read-only disclosure.

CVSS severity7.1
High
EPSS probability0.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect permission assignment in F5 BIG-IP and BIG-IQ allows attackers with authenticated access to view adjacent network information. The tmsh arp and ndp commands on both products, plus BIG-IP iControl REST, expose neighbor data under permissions broader than intended. BIG-IP is network-reachable with low privileges, while BIG-IQ requires local low-privileged access; the published impact is read-only disclosure.

The record

CVE
CVE-2026-42937
Published
May 13, 2026
Updated
May 13, 2026
Vendor
F5 Networks
Product
BIG-IP
Classifications
CWE-732, T1016
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 13, 2026CVE publishedPublication date reported by the CVE source.
  2. May 13, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=16.1.0 <*
  2. Affected versionversion=17.1.0 <17.1.3.2
  3. Affected versionversion=17.5.0 <17.5.1.6
  4. Affected versionversion=21.0.0 <21.0.0.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

F5 Networks · BIG-IPversion=16.1.0 <*; version=17.1.0 <17.1.3.2; version=17.5.0 <17.5.1.6; version=21.0.0 <21.0.0.2
F5 Networks · BIG-IQversion=8.4.0 <*

Published CVSS scores

5.5F5 Networks — BIG-IQ scenarioCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
6.8F5 Networks — BIG-IQ scenarioCVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
6.5F5 Networks — BIG-IP scenarioCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
7.1F5 Networks — BIG-IP scenarioCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-732Incorrect Permission Assignment for Critical Resource
T1016System Network Configuration Discovery

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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