Cyber Resilience

CVE-2025-59699

Auth Bypass in Entrust Nshield 5C Firmware ≤ 13.6.12

Public PoCAuth Bypass
Published
02 December 2025
Modified
08 December 2025
Patch / advisory
CVSS Score v3.1 6.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0028 21th percentile
Risk Priority 45 floored blend · peak EPSS

Summary

CVE-2025-59699 is a medium-severity Authentication Bypass by Spoofing (CWE-290) vulnerability in Entrust Nshield 5C Firmware. Its CVSS base score is 6.8 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 21th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to PE-3 (Physical Access Control) and SC-41 (Port and I/O Device Access) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

Entrust nShield Connect XC, nShield 5c, and nShield HSMi through 13.6.11, or 13.7, allow a physically proximate attacker to escalate privileges by booting from a USB device with a valid root filesystem. This occurs because of insecure default settings in…

more

the Legacy GRUB Bootloader.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
T1542 Pre-OS Boot Stealth
Adversaries may abuse Pre-OS Boot mechanisms as a way to establish persistence on a system.
T1542.001 System Firmware Stealth
Adversaries may modify system firmware to persist on systems.
T1542.002 Component Firmware Stealth
Adversaries may modify component firmware to persist on systems.
T1542.003 Bootkit Stealth
Adversaries may use bootkits to persist on systems.
T1070 Indicator Removal Stealth
Adversaries may selectively delete or modify artifacts generated to reduce indications of their presence and blend in with legitimate activity.
T1685.006 Clear Linux or Mac System Logs Defense Impairment
Adversaries may clear system logs to hide evidence of an intrusion.
Why these techniques?

Vulnerabilities enable physical privilege escalation via insecure GRUB USB boot (T1068), persistent compromise through unprotected boot chain and firmware modification via JTAG or upgrades (T1542/T1542.001-003), and indicator removal by editing unencrypted tamper logs (T1070/T1070.002) without detection or traces.

CVEs Like This One

CVE-2025-59697Same product: Entrust Nshield 5C
CVE-2025-59700Same product: Entrust Nshield 5C
CVE-2025-59698Same product: Entrust Nshield 5C
CVE-2025-59704Same product: Entrust Nshield 5C
CVE-2025-59703Same product: Entrust Nshield 5C
CVE-2025-59702Same product: Entrust Nshield 5C
CVE-2025-59695Same product: Entrust Nshield 5C
CVE-2025-59696Same product: Entrust Nshield 5C
CVE-2025-59693Same product: Entrust Nshield 5C
CVE-2025-59705Same product: Entrust Nshield 5C

Affected Assets

entrust
nshield 5c firmware
≤ 13.6.12 · 13.7 — 13.9.0
entrust
nshield hsmi firmware
≤ 13.6.12 · 13.7 — 13.9.0
entrust
nshield connect xc base firmware
≤ 13.6.12 · 13.7 — 13.9.0
entrust
nshield connect xc mid firmware
≤ 13.6.12 · 13.7 — 13.9.0
entrust
nshield connect xc high firmware
≤ 13.6.12 · 13.7 — 13.9.0

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)
  • PE-3 Physical Access Control
  • SC-41 Port and I/O Device Access
  • CM-6 Configuration Settings
Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)
  • 3 hardening rules · 3 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V6.4.3
  • V10.4.16
  • V10.5.1
  • V11.4.3

Mitigating Controls (NIST 800-53 r5) AI

prevent

Directly blocks the physically proximate attacker from reaching the HSM to insert a USB boot device.

prevent

Explicitly disables or removes USB ports/I/O devices so the Legacy GRUB USB-boot vector cannot be used.

prevent

Requires secure baseline settings that override the insecure default GRUB configuration allowing unauthorized root-filesystem boots.

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.AA-04 full match
prevents

Protecting, conveying, and verifying identity assertions specifically prevents the spoofing that enables authentication bypass.

PR.AA-03 mostly match
prevents

Requiring authentication of users/services/hardware directly counters spoofing-based bypass when strong methods are used.

PR.AA-02 partial match
prevents

Proofing and binding identities reduces spoofing opportunities during enrollment but does not address runtime authentication implementation flaws.

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.

degrades

Secure authentication control directly mitigates authentication bypass by spoofing.

degrades

Authentication information management directly addresses credential handling that prevents spoofing.

detects

Security testing can detect spoofing vulnerabilities but does not prevent them by itself.

prevents

Access control policy reduces spoofing opportunities but does not prescribe authentication mechanisms.

prevents

Identity management supports unique identities but does not guarantee resistance to spoofing.

prevents

Access rights assignment limits exposure but does not enforce authentication strength.

References