Cyber Resilience

CVE-2025-11845

Memory Safety in Zyxel Px3321-T1 Firmware ≤ 5.44\(achk.3\)c0

Published
24 February 2026
Modified
25 February 2026
Patch / advisory
CVSS Score v3.1 4.9
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
EPSS Score 0.0078 53th percentile
Risk Priority 40 floored blend · peak EPSS

Summary

CVE-2025-11845 is a medium-severity NULL Pointer Dereference (CWE-476) vulnerability in Zyxel Px3321-T1 Firmware. Its CVSS base score is 4.9 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Endpoint Denial of Service (T1499); ranked in the top 47% of CVEs by exploit likelihood; 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 SA-15 (Development Process, Standards, and Tools) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

A null pointer dereference vulnerability in the certificate downloader CGI program of the Zyxel VMG3625-T50B firmware versions through 5.50(ABPM.9.6)C0 and the Zyxel WX3100-T0 firmware versions through 5.50(ABVL.4.8)C0 could allow an authenticated attacker with administrator privileges to trigger a denial-of-service (DoS)…

more

condition by sending a crafted HTTP request.

CWE(s)

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.
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.
T1489 Service Stop Impact
Adversaries may stop or disable services on a system to render those services unavailable to legitimate users.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2025-11846Same product: Zyxel Ax7501-B1
CVE-2025-11847Same product: Zyxel Ax7501-B1
CVE-2025-11848Same product: Zyxel Ax7501-B1
CVE-2024-42058Same vendor: Zyxel
CVE-2023-6397Same vendor: Zyxel
CVE-2025-13943Same product: Zyxel Ax7501-B1
CVE-2025-6599Same product: Zyxel Ax7501-B1
CVE-2025-8693Same product: Zyxel Ax7501-B1
CVE-2026-1460Same product: Zyxel Ax7501-B1
CVE-2024-38268Same product: Zyxel Ax7501-B1

Affected Assets

zyxel
lte3301-plus firmware
≤ 1.00\(abqu.9\)c0
zyxel
nebula fwa505 firmware
≤ 1.60\(acko.2\)v0
zyxel
nebula fwa510 firmware
≤ 1.60\(acgd.0\)c0
zyxel
nebula fwa515 firmware
≤ 1.60\(acpz.0\)v0
zyxel
nebula fwa710 firmware
≤ 1.60\(acgc.1\)v0
zyxel
ee5301-00 firmware
≤ 5.63\(acld.2.1\)c0
zyxel
ee3301-00 firmware
≤ 5.63\(acmu.2.1\)c0
zyxel
dx5401-b1 firmware
≤ 5.17\(abyo.7.1\)c0
zyxel
dx4510-b1 firmware
≤ 5.17\(abyl.10.1\)c0
zyxel
dx4510-b0 firmware
≤ 5.17\(abyl.10.1\)c0
+44 more product configuration(s) — see NVD for full list

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

Developer testing and evaluation (including static analysis) directly finds null-dereference bugs before deployment.

Documented development standards and tools can enforce null-safety rules and safe pointer usage.

Engineering principles can mandate defensive coding such as explicit null checks before dereference.

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.

PR.PS-06 mostly match
prevents

Secure SDLC practices (static analysis, code review, safe coding standards) directly prevent NULL dereference bugs during development.

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.

finds

Security testing can detect NULL dereference defects before release.

prevents

Secure SDLC mandates defensive coding practices that can prevent NULL dereferences.

prevents

Application security requirements can specify input validation and pointer-safety rules.

prevents

Secure architecture principles encourage defensive design that avoids unsafe pointer use.

prevents

Secure coding standards directly require NULL-pointer checks and safe dereference patterns.

References