Security Resilience

CVE-2026-43845

Auth Bypass

Auth Bypass
Published
20 October 2026
Modified
20 October 2026
CVSS Score v4 9.2
Click a component to see what it means
Raw vectorCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/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 0.0045 39th percentile
Risk Priority 45 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). EPSS, Forum of Incident Response and Security Teams (FIRST), epss.first.org. Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2026-43845 is a critical-severity Weak Password Recovery Mechanism for Forgotten Password (CWE-640) vulnerability in Advantech (inferred from references). Its CVSS base score is 9.2 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Valid Accounts (T1078); ranked at the 39th 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 IA-12 (Identity Proofing) and IA-5 (Authenticator Management) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

A07:2025 Authentication Failures

EU & UK References

Vulnerability Data

A vulnerability in the password reset mechanism could allow an attacker to bypass the authentication mechanism.

CWE(s)
CWE-640

Related Threats

MITRE ATT&CK Enterprise Techniques

MITRE ATT&CK v20.0

T1078 Valid Accounts Stealth
Adversaries may obtain and abuse credentials of existing accounts as a means of gaining Initial Access, Persistence, Privilege Escalation, or Defense Evasion.
attack.mitre.org →
T1078.004 Cloud Accounts Stealth
Valid accounts in cloud environments may allow adversaries to perform actions to achieve Initial Access, Persistence, Privilege Escalation, or Defense Evasion.
attack.mitre.org →
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1531 Account Access Removal Impact
Adversaries may interrupt availability of system and network resources by inhibiting access to accounts utilized by legitimate users.
attack.mitre.org →
T1584.006 Web Services Resource Development
Adversaries may compromise access to third-party web services that can be used during targeting.
attack.mitre.org →
T1586 Compromise Accounts Resource Development
Adversaries may compromise accounts with services that can be used during targeting.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2025-6216Shared CWE-640
CVE-2025-0331Shared CWE-640
CVE-2026-50635Shared CWE-640
CVE-2025-7948Shared CWE-640
CVE-2026-70175Shared CWE-640
CVE-2024-6203Shared CWE-640
CVE-2025-53373Shared CWE-640
CVE-2025-12866Shared CWE-640
CVE-2025-10322Shared CWE-640
CVE-2026-108337Shared CWE-640

Affected Assets

Advantech
—
inferred from references and description; NVD did not file a CPE for this CVE

Mitigating Controls

Mitigating Controls (NIST 800-53 r5)

Our mappings, made for this CVE.

IA-12 Identity Proofing partial match

Identity proofing at appropriate assurance levels ensures forgotten-password recovery cannot succeed without strong verification of the user.

IA-5 Authenticator Management partial match

Authenticator management requires secure distribution, reset, and verification procedures that directly address weak password recovery flows.

Mitigating Controls (NIST CSF 2.0)

Our mappings, derived directly from the weakness types (CWEs) cited in the NVD entry via our CWE→CSF cross-walk — links open the control.

PR.AA-01 mostly match
blocks

Credential lifecycle management directly includes password reset/recovery flows.

PR.AA-02 mostly match
blocks

Identity proofing is the core control that prevents weak or bypassed recovery mechanisms.

PR.AA-03 partial match
blocks

Authentication policy covers strength/MFA but does not address recovery path weaknesses.

PR.PS-06 partial match
blocks

Secure SDLC reduces implementation flaws but is not specific to password-recovery design.

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

Our mappings, derived directly from the weakness types (CWEs) cited in the NVD entry via our CWE→ISO cross-walk — links open the control.

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

A.8.29's combined programme (code review, static analysis, vulnerability scanning, penetration testing) reaches CWE-640 from both SOURCE and RUNTIME angles: pentesters routinely exercise password recovery flows for brute-force, token reuse, and information disclosure (the exact failure modes in the 2024-2025 CVE examples), and code review catches implementation flaws like missing throttling or returning the original password; the remainder is design-level weaknesses (e.g., security questions that are too common or guessable from social media) where the code looks reasonable and the weakness only surfaces under a review of the recovery design itself.

A.8.28 Secure coding partial match
prevents

Secure-coding standards can prevent weak recovery implementations, yet the control is wider in scope.

References