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F5 BIG-IP EUVDEUVD-2026-29999

| CVE-2026-42409 HIGH
NULL Pointer Dereference (CWE-476)
2026-05-13 f5 GHSA-qj39-79pv-x52r
8.7
CVSS 4.0 · Vendor: f5
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Severity by source

Vendor (f5) PRIMARY
8.7 HIGH
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Primary rating from Vendor (f5) · only source for this CVE.

CVSS VectorVendor: f5

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
X

Lifecycle Timeline

4
Re-analysis Queued
May 13, 2026 - 16:22 vuln.today
cvss_changed
CVSS changed
May 13, 2026 - 16:22 NVD
7.5 (HIGH) 8.7 (HIGH)
Analysis Generated
May 13, 2026 - 15:48 vuln.today
CVE Published
May 13, 2026 - 14:12 nvd
HIGH 7.5

DescriptionCVE.org

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.

AnalysisAI

Remote unauthenticated attackers can crash F5 BIG-IP and BIG-IP Next Traffic Management Microkernel (TMM) processes via undisclosed malformed HTTP/2 requests when virtual servers are configured with both an HTTP/2 profile and iRules using HTTP::redirect or HTTP::respond commands. Exploitation requires no authentication or user interaction (CVSS AV:N/AC:L/PR:N/UI:N) and results in complete service disruption. Vendor patch available via F5 K000159034. EPSS data not provided, but the specific configuration requirement limits exposure to organizations using HTTP/2 with custom iRule redirects or responses.

Technical ContextAI

This null pointer dereference vulnerability (CWE-476) affects F5's Traffic Management Microkernel (TMM), the core data plane component responsible for processing all traffic through BIG-IP devices. TMM handles HTTP/2 frame processing, iRule execution, and connection management. The vulnerability occurs specifically when TMM processes certain HTTP/2 requests while executing iRule commands that manipulate HTTP responses (HTTP::redirect for 3xx redirects, HTTP::respond for custom responses). A null pointer dereference typically occurs when code attempts to access memory through an uninitialized or invalid pointer, causing immediate process termination in safety-critical systems. The affected CPE strings indicate impact across F5's entire next-generation product line: traditional BIG-IP appliances, BIG-IP Next SPK (Software for Per-app Virtual Editions), BIG-IP Next CNF (Cloud-Native Functions for containerized environments), and BIG-IP Next for Kubernetes. This suggests the vulnerable code exists in a shared HTTP/2 processing library across F5's modernized architecture.

RemediationAI

Apply vendor-released patches specified in F5 Security Advisory K000159034 (https://my.f5.com/manage/s/article/K000159034), which provides version-specific fixes for BIG-IP, BIG-IP Next SPK, BIG-IP Next CNF, and BIG-IP Next for Kubernetes platforms. Exact fixed versions are not provided in the CVE data but are documented in the advisory, which requires F5 customer portal access. Before patching, organizations can implement compensating controls with trade-offs: (1) Disable HTTP/2 profiles on affected virtual servers and revert to HTTP/1.1 - this eliminates vulnerability but sacrifices HTTP/2 performance benefits including multiplexing, header compression, and server push; client applications expecting HTTP/2 may experience compatibility issues. (2) Temporarily remove or comment out HTTP::redirect and HTTP::respond commands from iRules and implement redirects/custom responses at the application layer instead - this shifts logic from the load balancer to backend servers, increasing application complexity and potentially reducing redirect performance. (3) Implement connection rate limiting and HTTP/2 stream limits to slow potential exploitation attempts - this reduces attack surface but may impact legitimate high-volume traffic. Organizations running EoTS versions with no patch path should prioritize migration to supported BIG-IP releases or consider alternative application delivery solutions.

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EUVD-2026-29999 vulnerability details – vuln.today

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