dbcve.org
Big Ip Access Policy ManagerApplication · F5

CVE-2020-5924

MEDIUM · 5.3 CVSS v3.1 Published 2020-08-26
Fix available
A fix is available. Upgrade to 12.1.5.2 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
In BIG-IP APM versions 12.1.0-12.1.5.1 and 11.6.1-11.6.5.2, RADIUS authentication leaks memory when the username for authentication is not set.

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 · high confidence

BIG-IP APM contains a memory leak vulnerability in its RADIUS authentication module. When an authentication request is processed without a username set (empty or missing), the system fails to properly deallocate memory, causing a memory leak with each such request. Over time, repeated unauthenticated requests can exhaust available memory, leading to denial of service.

MitigationUpgrade BIG-IP APM to a patched version (13.1.0 or later for 13.x branch, or 14.1.0 or later for 14.x branch, or 15.1.0 or later for 15.x branch) or apply the appropriate hotfix. Also consider rate-limiting RADIUS authentication attempts at the network perimeter as a defensive measure.

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:>= 11.6.1, <= 11.6.5>= 12.1.0, < 12.1.5.2

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
None
Integrity
None
Availability
Low

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

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. Check BIG-IP version
    Run `tmsh show sys version` or inspect `/etc/product_version` to determine the installed BIG-IP version.
    Affected if The version falls within 11.6.1 to 11.6.5, or 12.1.0 to 12.1.5.2.
  2. Verify APM module is licensed and running
    Run `tmsh show apm status` or check the GUI under System > Software Management > Volume Setup to confirm the APM module is installed and licensed.
    Affected if APM is installed and the version is within the affected ranges.
  3. Confirm RADIUS authentication profile is configured
    Run `tmsh list apm profile access` and `tmsh list apm policy access-policy` to list APM access profiles and their associated RADIUS servers. Alternatively, check the GUI under Access Policy > Access Profiles List.
    Affected if An access profile exists with a RADIUS authentication server configured.
  4. Review APM logs for unauthenticated requests
    Run `tmsh show ltm log` or check `/var/log/apm` for entries containing RADIUS authentication failures with empty or missing username fields.
    Affected if Log entries show repeated RADIUS auth attempts with empty/missing usernames.
  5. Check system memory usage
    Run `tmsh show sys memory` or `bigtop -m` to monitor memory consumption over time. Compare current memory usage to baseline.
    Affected if Memory usage shows continuous growth without recovery, particularly if correlated with RADIUS auth activity.

If BIG-IP APM is running an affected version (11.6.1-11.6.5 or 12.1.0-12.1.5.2) with RADIUS authentication configured, and memory growth correlates with RADIUS requests lacking usernames, the environment is likely affected.

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 12.1.5.2 or later
Fixed in 12.1.5.2
Interim mitigation

Upgrade BIG-IP APM to a patched version (13.1.0 or later for 13.x branch, or 14.1.0 or later for 14.x branch, or 15.1.0 or later for 15.x branch) or apply the appropriate hotfix. Also consider rate-limiting RADIUS authentication attempts at the network perimeter as a defensive measure.

Fix this in Big Ip Access Policy Manager Scoped from the published advisory
  • Consultation4.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA4.0 h
18.0 hours of engineering $3,140
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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-2020-5924 in production — separate from our analysis above.

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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
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  • Version or environment caveats, and links to real fixes
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