CyberSecBulletin
CVE-2023-40534NVD status: Modified

BIG-IP: Missing Release of Memory after Effective Lifetime

Published Updated By the CyberSecBulletin desk

CVE-2023-40534 is a high-severity missing release of memory after effective lifetime vulnerability in BIG-IP from F5, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 17.1.0.3.0.23.4-ENG, 16.1.4.1.0.13.5-ENG as the first without the flaw, so updating BIG-IP to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.65% chance of exploitation within 30 days, higher than 52% of scored CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update BIG-IP to 17.1.0.3.0.23.4-ENG or 16.1.4.1.0.13.5-ENG, whichever matches your release line, or a later version.
  2. Update Big-ip Access Policy Manager to 16.1.4.1 or a later version.
  3. Update Big-ip Advanced Firewall Manager to 16.1.4.1 or a later version.
  4. Read the advisory on my.f5.com for workarounds and exact fixed builds.
  5. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
F5BIG-IP17.1.0 up to, but not including, 17.1.0.3.0.23.4-ENG; 16.1.0 up to, but not including, 16.1.4.1.0.13.5-ENG17.1.0.3.0.23.4-ENG, 16.1.4.1.0.13.5-ENG
F5BIG-IP Next SPK1.6.0 and laterNot stated
F5Big-ip Access Policy Manager16.1.0 up to, but not including, 16.1.4.1; 17.1.016.1.4.1
F5Big-ip Advanced Firewall Manager16.1.0 up to, but not including, 16.1.4.1; 17.1.016.1.4.1
F5Big-ip Advanced Web Application Firewall16.1.0 up to, but not including, 16.1.4.1; 17.1.016.1.4.1
F5Big-ip Analytics16.1.0 up to, but not including, 16.1.4.1; 17.1.016.1.4.1
F5Big-ip Application Acceleration Manager16.1.0 up to, but not including, 16.1.4.1; 17.1.016.1.4.1
F5Big-ip Application Security Manager16.1.0 up to, but not including, 16.1.4.1; 17.1.016.1.4.1
F5Big-ip Application Visibility And Reporting16.1.0 up to, but not including, 16.1.4.1; 17.1.016.1.4.1
F5Big-ip Carrier-grade Nat16.1.0 up to, but not including, 16.1.4.1; 17.1.016.1.4.1
F5Big-ip Ddos Hybrid Defender16.1.0 up to, but not including, 16.1.4.1; 17.1.016.1.4.1
F5Big-ip Domain Name System16.1.0 up to, but not including, 16.1.4.1; 17.1.016.1.4.1
F5Big-ip Edge Gateway16.1.0 up to, but not including, 16.1.4.1; 17.1.016.1.4.1
F5Big-ip Fraud Protection Service16.1.0 up to, but not including, 16.1.4.1; 17.1.016.1.4.1
F5Big-ip Global Traffic Manager16.1.0 up to, but not including, 16.1.4.1; 17.1.016.1.4.1
F5Big-ip Link Controller16.1.0 up to, but not including, 16.1.4.1; 17.1.016.1.4.1
F5Big-ip Local Traffic Manager16.1.0 up to, but not including, 16.1.4.1; 17.1.016.1.4.1
F5Big-ip Next Service Proxy For Kubernetes1.6.0 through 1.8.2Not stated
F5Big-ip Policy Enforcement Manager16.1.0 up to, but not including, 16.1.4.1; 17.1.016.1.4.1
F5Big-ip SSL Orchestrator16.1.0 up to, but not including, 16.1.4.1; 17.1.016.1.4.1
F5Big-ip Webaccelerator16.1.0 up to, but not including, 16.1.4.1; 17.1.016.1.4.1
F5Big-ip Websafe16.1.0 up to, but not including, 16.1.4.1; 17.1.016.1.4.1

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
NoneNo data is disclosed.
Integrity
NoneNothing can be modified.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by CNA (f5.com).

Official description

When a client-side HTTP/2 profile and the HTTP MRF Router option are enabled for a virtual server, and an iRule using the HTTP_REQUEST event or Local Traffic Policy are associated with the virtual server, undisclosed requests can cause TMM to terminate. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Missing Release of Memory after Effective Lifetime

The product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.

How developers prevent this class of flaw

  • Choose a language or tool that provides automatic memory management, or makes manual memory management less error-prone. For example, glibc in Linux provides protection against free of invalid pointers. When using Xcode to target OS X or iOS, enable automatic reference counting (ARC). To help correctly and consistently manage memory when programming in C++, consider using a smart pointer class such as std
  • Use an abstraction library to abstract away risky APIs. Not a complete solution.
  • Consider using the Boehm-Demers-Weiser garbage collector (bdwgc), which can help avoid leaks.

More Missing Release of Memory after Effective Lifetime vulnerabilities (CWE-401)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in BIG-IP

All BIG-IP vulnerabilities

Recent Missing Release of Memory after Effective Lifetime vulnerabilities

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