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Big Ip Access Policy ManagerApplication · F5

CVE-2021-22999

HIGH · 7.5 CVSS v3.1 Published 2021-03-31
Fix available
A fix is available. Upgrade to 14.1.4 / 15.1.0 or later.
See remediation →
84/100
Remediation priority · High
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 versions 15.0.x before 15.1.0 and 14.1.x before 14.1.4, the BIG-IP system provides an option to connect HTTP/2 clients to HTTP/1.x servers. When a client is slow to accept responses and it closes a connection prematurely, the BIG-IP system may indefinitely retain some streams unclosed. Note: Software versions which have reached End of Software Development (EoSD) 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

This vulnerability exists in BIG-IP's HTTP/2 to HTTP/1.x proxy functionality. When HTTP/2 clients are slow to accept responses and close connections prematurely, the BIG-IP system may fail to properly close associated streams, causing indefinite retention of unclosed streams and potential resource exhaustion (denial of service).

MitigationUpgrade BIG-IP to version 15.1.0 or 14.1.4 or later. Alternatively, disable HTTP/2 to HTTP/1.x conversion if not required in the environment.

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:>= 14.1.0, < 14.1.4>= 15.0.0, < 15.1.0
Big Ip Advanced Firewall ManagerApplication
Affected:>= 14.1.0, < 14.1.4>= 15.0.0, < 15.1.0
Big Ip Advanced Web Application FirewallApplication
Affected:>= 14.1.0, < 14.1.4>= 15.0.0, < 15.1.0
Big Ip AnalyticsApplication
Affected:>= 14.1.0, < 14.1.4>= 15.0.0, < 15.1.0
Big Ip Application Acceleration ManagerApplication
Affected:>= 14.1.0, < 14.1.4>= 15.0.0, < 15.1.0
Big Ip Application Security ManagerApplication
Affected:>= 14.1.0, < 14.1.4>= 15.0.0, < 15.1.0
Big Ip Ddos Hybrid DefenderApplication
Affected:>= 14.1.0, < 14.1.4>= 15.0.0, < 15.1.0
Big Ip Domain Name SystemApplication
Affected:>= 14.1.0, < 14.1.4>= 15.0.0, < 15.1.0

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
High

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

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 system version
    Run 'tmsh show sys version' or 'bigtopctl version' to retrieve the installed BIG-IP version
    Affected if Version is 14.1.0-14.1.3.x or 15.0.0-15.0.x (falls within 14.1.0 <= version < 14.1.4 or 15.0.0 <= version < 15.1.0)
  2. Verify HTTP/2 profile is configured
    Run 'tmsh list ltm http2' to list all HTTP/2 profiles configured on the system
    Affected if Any HTTP/2 profile exists on the system
  3. Confirm HTTP/2 to HTTP/1.x conversion is enabled
    Run 'tmsh list ltm http2 <profile_name>' for each HTTP/2 profile and check if 'http2-to-http-1' setting is enabled, or inspect the associated VIP configuration for HTTP/2 profile assignment
    Affected if HTTP/2 to HTTP/1.x conversion (http2-to-http-1) is explicitly enabled in the profile or virtual server configuration
  4. Identify active modules that use HTTP/2 proxy
    Run 'tmsh show sys module' or check which BIG-IP modules (APM, AFM, ASM, etc.) are provisioned and active
    Affected if Any of the affected modules (APM, AFM, AWM, Analytics, AAM, ASM, DNS, DDoS Hybrid Defender) are provisioned and actively processing HTTP/2 traffic

You are affected if the system runs a vulnerable version (14.1.0-14.1.3.x or 15.0.0-15.0.x) AND has HTTP/2 to HTTP/1.x conversion enabled in any profile used by active virtual servers.

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 14.1.4 / 15.1.0 or later
Fixed in 14.1.415.1.0
Interim mitigation

Upgrade BIG-IP to version 15.1.0 or 14.1.4 or later. Alternatively, disable HTTP/2 to HTTP/1.x conversion if not required in the environment.

Fix this in Big Ip Access Policy Manager Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,080
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,328.

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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-2021-22999 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