F5 BIG-IP Traffic Management Microkernel respond null pointer dereference

CVSS Meta Temp Score
CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.
Current Exploit Price (≈)
Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.
CTI Interest Score
Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
7.3$0-$5k0.00

Summaryinfo

A vulnerability, which was classified as problematic, has been found in F5 BIG-IP, BIG-IP Next SPK, BIG-IP Next CNF and BIG-IP Next for Kubernetes. The affected element is the function HTTP::redirect/HTTP::respond of the component Traffic Management Microkernel. Performing a manipulation results in null pointer dereference. This vulnerability is reported as CVE-2026-42409. The attack is possible to be carried out remotely. No exploit exists. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, was found in F5 BIG-IP, BIG-IP Next SPK, BIG-IP Next CNF and BIG-IP Next for Kubernetes (affected version unknown). This affects the function HTTP::redirect/HTTP::respond of the component Traffic Management Microkernel. The manipulation with an unknown input leads to a null pointer dereference vulnerability. CWE is classifying the issue as CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. This is going to have an impact on availability. The summary by CVE is:

When an HTTP/2 profile and an iRule containing the HTTP::redirect or HTTP::respond command are configured on a virtual server, undisclosed requests can cause the Traffic Management Microkernel (TMM) process to terminate.  Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

It is possible to read the advisory at my.f5.com. This vulnerability is uniquely identified as CVE-2026-42409 since 05/01/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 05/24/2026).

The vulnerability scanner Nessus provides a plugin with the ID 316109 (F5 Networks BIG-IP : BIG-IP HTTP/2 vulnerability (K000159034)), which helps to determine the existence of the flaw in a target environment.

Upgrading eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (316109) and CERT Bund (WID-SEC-2026-1532). Be aware that VulDB is the high quality source for vulnerability data.

Affected

  • F5 BIG-IP

Productinfo

Type

Vendor

Name

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 7.5
VulDB Meta Temp Score: 7.3

VulDB Base Score: 7.5
VulDB Temp Score: 7.2
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 7.5
CNA Vector: 🔒

CVSSv2info

AVACAuCIA
💳💳💳💳💳💳
💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock

VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Null pointer dereference
CWE: CWE-476 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-DayUnlockUnlockUnlockUnlock
TodayUnlockUnlockUnlockUnlock

Nessus ID: 316109
Nessus Name: F5 Networks BIG-IP : BIG-IP HTTP/2 vulnerability (K000159034)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Timelineinfo

05/01/2026 CVE reserved
05/13/2026 +12 days Advisory disclosed
05/13/2026 +0 days VulDB entry created
05/24/2026 +11 days VulDB entry last update

Sourcesinfo

Vendor: f5.com

Advisory: K000159034
Status: Confirmed

CVE: CVE-2026-42409 (🔒)
GCVE (CVE): GCVE-0-2026-42409
GCVE (VulDB): GCVE-100-363567
CERT Bund: WID-SEC-2026-1532 - F5 BIG-IP Produkte: Mehrere Schwachstellen

Entryinfo

Created: 05/13/2026 17:44
Updated: 05/24/2026 23:29
Changes: 05/13/2026 17:44 (76), 05/17/2026 16:33 (7), 05/24/2026 23:29 (2)
Complete: 🔍
Cache ID: 216::103

Be aware that VulDB is the high quality source for vulnerability data.

Discussion

No comments yet. Languages: en.

Please log in to comment.

◂ PreviousOverviewNext ▸

Want to stay up to date on a daily basis?

Enable the mail alert feature now!