CyberSecBulletin
CVE-2026-41957NVD status: Analyzed

BIG-IP: Deserialization of Untrusted Data

Published Updated By the CyberSecBulletin desk

CVE-2026-41957 is a high-severity deserialization of untrusted data vulnerability in BIG-IP from F5, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, 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 0.51% 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-IQ to 8.4.1 or a later version.
  3. Read the advisory on my.f5.com for workarounds and exact fixed builds.

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-IQ8.4.0 up to, but not including, 8.4.18.4.1
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-iq Centralized Management8.4.0Not 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
LowA basic user account is enough.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

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

Scoring systemScoreSeverityScored by
CVSS 4.08.7HighCNA (f5.com)
CVSS 3.18.8HighCNA (f5.com)

Official description

An authenticated remote code execution vulnerability through undisclosed vectors exists in the BIG-IP and BIG-IQ Configuration utility. 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: Deserialization of Untrusted Data

The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.

How developers prevent this class of flaw

  • If available, use the signing/sealing features of the programming language to assure that deserialized data has not been tainted. For example, a hash-based message authentication code (HMAC) could be used to ensure that data has not been modified.
  • When deserializing data, populate a new object rather than just deserializing. The result is that the data flows through safe input validation and that the functions are safe.
  • Explicitly define a final object() to prevent deserialization.

More Deserialization of Untrusted Data vulnerabilities (CWE-502)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in BIG-IP

All BIG-IP vulnerabilities

Recent Deserialization of Untrusted Data vulnerabilities

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