dbcve.org
Big Ip Advanced Web Application FirewallApplication · F5

CVE-2021-23053

MEDIUM · 5.3 CVSS v3.1 Published 2021-09-14
Fix available
A fix is available. Upgrade to 13.1.3.6 / 14.1.3.1 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
On version 15.1.x before 15.1.3, 14.1.x before 14.1.3.1, and 13.1.x before 13.1.3.6, when the brute force protection feature of BIG-IP Advanced WAF or BIG-IP ASM is enabled on a virtual server and the virtual server is under brute force attack, the MySQL database may run out of disk space due to lack of row limit on undisclosed tables in the MYSQL database. 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

In F5 BIG-IP Advanced WAF and ASM, the brute force protection feature lacks proper row limits on MySQL database tables. When a virtual server with this feature enabled is under brute force attack, the database grows unbounded and can exhaust disk space, causing denial of service.

MitigationUpgrade BIG-IP to version 15.1.3+, 14.1.3.1+, or 13.1.3.6+ to patch the vulnerability. Alternatively, if brute force protection is not required, it can be disabled.

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 Advanced Web Application FirewallApplication
Affected:>= 13.1.0, < 13.1.3.6>= 14.1.0, < 14.1.3.1>= 15.1.0, < 15.1.3
Big Ip Application Security ManagerApplication
Affected:>= 13.1.0, < 13.1.3.6>= 14.1.0, < 14.1.3.1>= 15.1.0, < 15.1.3

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 check the web UI under Dashboard > Overview > System > Software Version
    Affected if The version falls within 13.1.0 to <13.1.3.6, 14.1.0 to <14.1.3.1, or 15.1.0 to <15.1.3
  2. Verify ASM or Advanced WAF module is provisioned
    Run 'tmsh list /sys provision' and look for asm or awaf provision level set to nominal or dedicated
    Affected if ASM or Advanced WAF is provisioned (not 'none') on the device
  3. Confirm brute force protection is enabled
    Navigate to Security > Brute Force Protection in the web UI, or run 'tmsh list /asm policy' to list ASM policies with brute force configuration
    Affected if Any brute force profile or policy is active on virtual servers

You are affected if your BIG-IP runs a vulnerable version (13.1.0-13.1.3.5, 14.1.0-14.1.3.0, or 15.1.0-15.1.2), has ASM or Advanced WAF provisioned, and has brute force protection enabled on any virtual server.

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.

dbcve · scoped
Upgrade available Upgrade to 13.1.3.6 / 14.1.3.1 / 15.1.3 or later
Fixed in 13.1.3.614.1.3.115.1.3
Interim mitigation

Upgrade BIG-IP to version 15.1.3+, 14.1.3.1+, or 13.1.3.6+ to patch the vulnerability. Alternatively, if brute force protection is not required, it can be disabled.

Recommended fix High confidence

Upgrade to BIG-IP 13.1.3.6, 14.1.3.1, or 15.1.3 (or later stable releases within your major version branch)

  1. 1. Back up the current BIG-IP configuration using the Configuration Utility or tmsh command: 'tmsh save sys config'
  2. 2. Download the appropriate fixed version from F5 Networks support portal (13.1.3.6, 14.1.3.1, or 15.1.3)
  3. 3. Upload the ISO image to the BIG-IP device via the Configuration Utility or SCP
  4. 4. Boot from the ISO image and run the software installation wizard, or use tmsh to install the volume
  5. 5. After installation, reboot the device to boot from the new volume
  6. 6. Verify the brute force protection feature is still enabled and functioning correctly after upgrade
  7. 7. Confirm MySQL database space usage is now properly constrained under brute force attack conditions
Caveat Ensure compatibility with your current BIG-IP configuration and test in non-production environment before deploying to production; verify that any custom iRules or policies work with the new version

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Big Ip Advanced Web Application Firewall Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,120.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2021-23053 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2021-23053 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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