Cyber Resilience

CVE-2026-42920

DoS in F5 Big-Ip Access Policy Manager 17.1.0 – 17.1.3

DoS
Published
13 May 2026
Modified
18 June 2026
Patch / advisory
View advisory
CVSS Score v4 8.7
Click a component to see what it means
Raw vectorCVSS: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
EPSS Score 0.0026 18th percentile
Risk Priority 43 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2026-42920 is a high-severity Infinite Loop (CWE-835) vulnerability in F5 Big-Ip Access Policy Manager. Its CVSS base score is 8.7 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Endpoint Denial of Service (T1499); ranked at the 18th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-2 (Flaw Remediation) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

When a Client SSL profile is configured with Allow Dynamic Record Sizing on a UDP virtual server, undisclosed traffic can cause the Traffic Management Microkernel (TMM) to terminate. Note: Software versions which have reached End of Technical Support (EoTS) are…

more

not evaluated.

CWE(s)
CWE-835

Related Threats

MITRE ATT&CK Enterprise Techniques

T1499 Endpoint Denial of Service Impact
Adversaries may perform Endpoint Denial of Service (DoS) attacks to degrade or block the availability of services to users.
attack.mitre.org →
T1499.003 Application Exhaustion Flood Impact
Adversaries may target resource intensive features of applications to cause a denial of service (DoS), denying availability to those applications.
attack.mitre.org →
T1499.004 Application or System Exploitation Impact
Adversaries may exploit software vulnerabilities that can cause an application or system to crash and deny availability to users.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-42781Same product: F5 Big-Ip Access Policy Manager
CVE-2025-21091Same product: F5 Big-Ip Access Policy Manager
CVE-2026-34019Same product: F5 Big-Ip Access Policy Manager
CVE-2025-20045Same product: F5 Big-Ip Access Policy Manager
CVE-2025-52585Same product: F5 Big-Ip Access Policy Manager
CVE-2025-41433Same product: F5 Big-Ip Access Policy Manager
CVE-2023-29163Same product: F5 Big-Ip Access Policy Manager
CVE-2024-25560Same product: F5 Big-Ip Access Policy Manager
CVE-2025-58153Same product: F5 Big-Ip Access Policy Manager
CVE-2023-40534Same product: F5 Big-Ip Access Policy Manager

Affected Assets

f5
big-ip access policy manager
21.0.0 · 17.1.0 — 17.1.3 · 17.5.0 — 17.5.1 · 16.1.0 — 16.1.6
f5
big-ip advanced firewall manager
21.0.0 · 17.1.0 — 17.1.3 · 17.5.0 — 17.5.1 · 16.1.0 — 16.1.6
f5
big-ip advanced web application firewall
21.0.0 · 17.1.0 — 17.1.3 · 17.5.0 — 17.5.1 · 16.1.0 — 16.1.6
f5
big-ip analytics
21.0.0 · 17.1.0 — 17.1.3 · 17.5.0 — 17.5.1 · 16.1.0 — 16.1.6
f5
big-ip application acceleration manager
21.0.0 · 17.1.0 — 17.1.3 · 17.5.0 — 17.5.1 · 16.1.0 — 16.1.6
f5
big-ip application security manager
21.0.0 · 17.1.0 — 17.1.3 · 17.5.0 — 17.5.1 · 16.1.0 — 16.1.6
f5
big-ip application visibility and reporting
21.0.0 · 17.1.0 — 17.1.3 · 17.5.0 — 17.5.1 · 16.1.0 — 16.1.6
f5
big-ip automation toolchain
21.0.0 · 17.1.0 — 17.1.3 · 17.5.0 — 17.5.1 · 16.1.0 — 16.1.6
f5
big-ip carrier-grade nat
21.0.0 · 17.1.0 — 17.1.3 · 17.5.0 — 17.5.1 · 16.1.0 — 16.1.6
f5
big-ip container ingress services
21.0.0 · 17.1.0 — 17.1.3 · 17.5.0 — 17.5.1 · 16.1.0 — 16.1.6
+11 more product configuration(s) — see NVD for full list

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

SA-11 Developer Testing and Evaluation good match

Developer testing and evaluation can discover unreachable loop exit conditions through static analysis, fuzzing, or execution tracing.

SI-2 Flaw Remediation good match

Flaw remediation processes identify and correct infinite-loop defects reported from testing or operations.

SA-15 Development Process, Standards, and Tools partial match

Requiring documented development processes and secure coding standards reduces introduction of loops whose termination conditions are unreachable.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

ID.RA-01 partial match
prevents

Static analysis and vuln scanning during asset assessment can detect unreachable loop exits.

PR.PS-06 partial match
prevents

Secure SDLC practices (reviews, testing, static analysis) directly prevent introduction of infinite-loop defects.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.25 Secure development life cycle partial match
prevents

Secure development life cycle mandates practices that can detect and prevent infinite-loop defects.

A.8.26 Application security requirements partial match
prevents

Application security requirements can specify loop-termination rules, indirectly reducing the weakness.

A.8.28 Secure coding partial match
prevents

Secure coding standards directly address loop termination and prevent infinite loops.

A.8.29 Security testing in development and acceptance partial match
finds

Security testing can uncover infinite-loop conditions before release.

References