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Big Ip Access Policy ManagerApplication · F5

CVE-2026-40435

MEDIUM · 5.3 CVSS v3.1 Published 2026-05-13
Fix available
A fix is available. Upgrade to after 17.5.1 or later.
See remediation →
62/100
Remediation priority · Elevated
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
When configured, IP-based access restrictions for httpd do not cover all endpoints, which may allow connections from blocked addresses.  Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

The httpd web server's IP-based access control configuration does not apply consistently across all endpoints. Certain routes or virtual hosts may bypass the configured allowlist/denylist rules, permitting connections from IP addresses that should be blocked.

MitigationAudit all httpd configuration files (including vhosts, .htaccess, and mod_authz_host directives) to ensure IP access restrictions are uniformly applied to all endpoints, or implement a centralized access control mechanism.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Big Ip Access Policy ManagerApplication
Affected:>= 17.1.0, <= 17.1.3>= 17.5.0, <= 17.5.1>= 16.1.0, <= 16.1.6
Big Ip Advanced Firewall ManagerApplication
Affected:>= 17.1.0, <= 17.1.3>= 17.5.0, <= 17.5.1>= 16.1.0, <= 16.1.6
Big Ip Advanced Web Application FirewallApplication
Affected:>= 17.1.0, <= 17.1.3>= 17.5.0, <= 17.5.1>= 16.1.0, <= 16.1.6
Big Ip AnalyticsApplication
Affected:>= 17.1.0, <= 17.1.3>= 17.5.0, <= 17.5.1>= 16.1.0, <= 16.1.6
Big Ip Application Acceleration ManagerApplication
Affected:>= 17.1.0, <= 17.1.3>= 17.5.0, <= 17.5.1>= 16.1.0, <= 16.1.6
Big Ip Application Security ManagerApplication
Affected:>= 17.1.0, <= 17.1.3>= 17.5.0, <= 17.5.1>= 16.1.0, <= 16.1.6
Big Ip Application Visibility And ReportingApplication
Affected:>= 17.1.0, <= 17.1.3>= 17.5.0, <= 17.5.1>= 16.1.0, <= 16.1.6
Big Ip Automation ToolchainApplication
Affected:>= 17.1.0, <= 17.1.3>= 17.5.0, <= 17.5.1>= 16.1.0, <= 16.1.6

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed Big IP version
    Run `tmsh show /sys version` or check the web UI under Dashboard > System > Software Version to determine the installed version number
    Affected if The version falls within 17.1.0-17.1.3, 17.5.0-17.5.1, or 16.1.0-16.1.6
  2. Locate httpd configuration files
    Inspect configuration files in /etc/httpd/conf/ and /etc/httpd/conf.d/ directories, or use `tmsh list /httpd` to list httpd-related configuration objects
    Affected if IP-based access control (Allow/Deny directives, Require ip, or iRule-based restrictions) is configured in any httpd config file or virtual server definition
  3. Identify virtual hosts with IP access control
    Search for `Allow`, `Deny`, `Require`, or `ttmsh ltm virtual` commands with `ip intelligence` or `datagroup` references in httpd configuration files
    Affected if Some virtual hosts or routes have IP access restrictions while others do not, creating inconsistent enforcement
  4. Check for iRules or LTM profiles controlling IP access
    Review LTM virtual server configurations using `tmsh list /ltm virtual all-properties` and look for iRules attached via `tmsh list /ltm rule all` that handle IP-based filtering
    Affected if IP access control is delegated to iRules or LTM profiles rather than being enforced uniformly at the httpd layer across all endpoints

You are affected if your Big IP version is 17.1.0-17.1.3, 17.1.0-17.1.3, 17.5.0-17.5.1, or 16.1.0-16.1.6 and you have httpd-based IP access control rules that may not be consistently applied to all virtual hosts or routes.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Upgrade available Upgrade to a release after 17.5.1
Interim mitigation

Audit all httpd configuration files (including vhosts, .htaccess, and mod_authz_host directives) to ensure IP access restrictions are uniformly applied to all endpoints, or implement a centralized access control mechanism.

Fix this in Big Ip Access Policy Manager Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing2.0 h
  • Review / QA1.0 h
9.0 hours of engineering $1,600
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,560.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-40435 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data