CyberSecBulletin
CVE-2026-41956NVD status: Analyzed

BIG-IP: Stack-based Buffer Overflow

Published Updated By the CyberSecBulletin desk

CVE-2026-41956 is a high-severity stack-based buffer overflow 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 17.5.1.4, 17.1.3.1 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 0.26% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update BIG-IP to 17.5.1.4 or 17.1.3.1, whichever matches your release line, or a later version.
  2. Update BIG-IP Next CNF to 2.0.3 or 1.4.1, whichever matches your release line, or a later version.
  3. Update BIG-IP Next for Kubernetes to 2.1.0 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-IP17.5.0 up to, but not including, 17.5.1.4; 17.1.0 up to, but not including, 17.1.3.1; 16.1.0 and later17.5.1.4, 17.1.3.1
F5BIG-IP Next CNF2.0.0 up to, but not including, 2.0.3; 1.4.0 up to, but not including, 1.4.12.0.3, 1.4.1
F5BIG-IP Next for Kubernetes2.0.0 up to, but not including, 2.1.02.1.0
F5Big-ip Access Policy Manager17.1.0 through 17.1.3; 17.5.0 through 17.5.1; 16.1.0 through 16.1.6Not stated
F5Big-ip Advanced Firewall Manager17.1.0 through 17.1.3; 17.5.0 through 17.5.1; 16.1.0 through 16.1.6Not stated
F5Big-ip Advanced Web Application Firewall17.1.0 through 17.1.3; 17.5.0 through 17.5.1; 16.1.0 through 16.1.6Not stated
F5Big-ip Analytics17.1.0 through 17.1.3; 17.5.0 through 17.5.1; 16.1.0 through 16.1.6Not stated
F5Big-ip Application Acceleration Manager17.1.0 through 17.1.3; 17.5.0 through 17.5.1; 16.1.0 through 16.1.6Not stated
F5Big-ip Application Security Manager17.1.0 through 17.1.3; 17.5.0 through 17.5.1; 16.1.0 through 16.1.6Not stated
F5Big-ip Application Visibility And Reporting17.1.0 through 17.1.3; 17.5.0 through 17.5.1; 16.1.0 through 16.1.6Not stated
F5Big-ip Automation Toolchain17.1.0 through 17.1.3; 17.5.0 through 17.5.1; 16.1.0 through 16.1.6Not stated
F5Big-ip Carrier-grade Nat17.1.0 through 17.1.3; 17.5.0 through 17.5.1; 16.1.0 through 16.1.6Not stated
F5Big-ip Container Ingress Services17.1.0 through 17.1.3; 17.5.0 through 17.5.1; 16.1.0 through 16.1.6Not stated
F5Big-ip Ddos Hybrid Defender17.1.0 through 17.1.3; 17.5.0 through 17.5.1; 16.1.0 through 16.1.6Not stated
F5Big-ip Domain Name System17.1.0 through 17.1.3; 17.5.0 through 17.5.1; 16.1.0 through 16.1.6Not stated
F5Big-ip Edge Gateway17.1.0 through 17.1.3; 17.5.0 through 17.5.1; 16.1.0 through 16.1.6Not stated
F5Big-ip Fraud Protection Service17.1.0 through 17.1.3; 17.5.0 through 17.5.1; 16.1.0 through 16.1.6Not stated
F5Big-ip Global Traffic Manager17.1.0 through 17.1.3; 17.5.0 through 17.5.1; 16.1.0 through 16.1.6Not stated
F5Big-ip Link Controller17.1.0 through 17.1.3; 17.5.0 through 17.5.1; 16.1.0 through 16.1.6Not stated
F5Big-ip Local Traffic Manager17.1.0 through 17.1.3; 17.5.0 through 17.5.1; 16.1.0 through 16.1.6Not stated
F5Big-ip Policy Enforcement Manager17.1.0 through 17.1.3; 17.5.0 through 17.5.1; 16.1.0 through 16.1.6Not stated
F5Big-ip SSL Orchestrator17.1.0 through 17.1.3; 17.5.0 through 17.5.1; 16.1.0 through 16.1.6Not stated
F5Big-ip Webaccelerator17.1.0 through 17.1.3; 17.5.0 through 17.5.1; 16.1.0 through 16.1.6Not stated
F5Big-ip Websafe17.1.0 through 17.1.3; 17.5.0 through 17.5.1; 16.1.0 through 16.1.6Not stated
F5Big-ip Next Cloud-native Network Functions2.0.0 through 2.0.2; 1.4.0Not stated

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).

Scoring systemScoreSeverityScored by
CVSS 4.08.7HighCNA (f5.com)
CVSS 3.17.5HighCNA (f5.com)

Official description

When a classification profile is configured on a UDP virtual server, undisclosed requests can cause the Traffic Management Microkernel (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: Stack-based Buffer Overflow

The product writes past the end of a buffer that was allocated on the stack.

How developers prevent this class of flaw

  • Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND discusses canary-based detection in detail.
  • Use an abstraction library to abstract away risky APIs. Not a complete solution.
  • Implement and perform bounds checking on input.

More Stack-based Buffer Overflow vulnerabilities (CWE-121)

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 Stack-based Buffer Overflow vulnerabilities

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