Cyber Resilience

CVE-2026-4639

Access Control in Gss Vitalsesp ≤ 6.3

Published
24 March 2026
Modified
15 April 2026
CVSS Score v4 8.7
Click a component to see what it means
Raw vectorCVSS:4.0/AV:N/AC:L/AT:N/PR:L/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 0.0030 23th percentile
Risk Priority 38 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-2026-4639 is a high-severity Incorrect Authorization (CWE-863) vulnerability in Gss Vitalsesp. Its CVSS base score is 8.7 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 23th 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 AC-24 (Access Control Decisions) and AC-25 (Reference Monitor) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2026-4639 is an Incorrect Authorization vulnerability (CWE-863) in Vitals ESP, a product developed by Galaxy Software Services. Published on 2026-03-24, it enables authenticated remote attackers to perform certain administrative functions, leading to privilege escalation. The vulnerability carries a CVSS v3.1 base score of 8.8 (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H), indicating high severity due to its network accessibility, low attack complexity, and significant impacts on confidentiality, integrity, and availability.

An attacker with low-level authenticated access over the network can exploit this flaw without user interaction. Successful exploitation allows the attacker to execute administrative actions beyond their intended privileges, potentially compromising the entire system by gaining unauthorized control over sensitive operations.

TWCERT advisories provide further details on the vulnerability, including mitigation recommendations, accessible at https://www.twcert.org.tw/en/cp-139-10795-25784-2.html and https://www.twcert.org.tw/tw/cp-132-10794-704a2-1.html. Security practitioners should consult these for specific patch information or workarounds from Galaxy Software Services.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

Vitals ESP developed by Galaxy Software Services has a Incorrect Authorization vulnerability, allowing authenticated remote attackers to perform certain administrative functions, thereby escalating privileges.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
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.
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
T1548 Abuse Elevation Control Mechanism Privilege Escalation
Adversaries may circumvent mechanisms designed to control privilege elevation to gain higher-level permissions.
T1548.002 Bypass User Account Control Privilege Escalation
Adversaries may bypass UAC mechanisms to elevate process privileges on system.
T1548.003 Sudo and Sudo Caching Privilege Escalation
Adversaries may perform sudo caching and/or use the sudoers file to elevate privileges.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2025-14254Same product: Gss Vitalsesp
CVE-2025-14253Same product: Gss Vitalsesp
CVE-2025-14255Same product: Gss Vitalsesp
CVE-2026-4640Same product: Gss Vitalsesp
CVE-2024-40771Shared CWE-863
CVE-2023-25923Shared CWE-863
CVE-2026-41660Shared CWE-863
CVE-2023-34197Shared CWE-863
CVE-2026-62231Shared CWE-863
CVE-2024-56348Shared CWE-863

Affected Assets

gss
vitalsesp
≤ 6.3

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)
  • 5 hardening rules · 3 OS baselines
Validate
Prove the fix (OWASP ASVS)

—

Mitigating Controls (NIST 800-53 r5) AI

AC-3 directly requires correct enforcement of authorization decisions on every access request, structurally preventing incorrect checks.

AC-24 ensures access-control decisions are made and applied consistently, reducing the chance of an incorrect authorization result.

A reference monitor that is always invoked and tamper-proof forces every authorization decision through a verified, correct path.

Least-privilege assignments shrink the set of authorizations that must be checked correctly, limiting exposure to flawed checks.

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-05 partial match
prevents

Defining, enforcing, and reviewing access authorizations and least privilege directly prevents incorrect authorization checks.

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.

prevents

Requiring consistency between access rights and classification plus formal approval steps ensures that the authorization logic correctly distinguishes between entities that should and should not be granted access.

prevents

Enforcing policy-driven approval and role-change reviews stops incorrect or stale authorization decisions from remaining in effect after job changes or terminations.

prevents

By tying access rights to identity, device, location and classification, the control reduces the likelihood that an authorization decision will be based on an incorrect or bypassed policy.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (higher-evidence rows only; rows rated `none` are excluded).

Oracle Linux 8 (2 rules)
  • V-248581 OL 8 must require users to provide a password for privilege escalation. prevents CWE-863
  • V-252656 The OL 8 operating system must not be configured to bypass password requirements for privilege escalation. prevents CWE-863
RHEL 7 (1 rule)
  • V-204430 The Red Hat Enterprise Linux operating system must be configured so that users must re-authenticate for privilege escalation. prevents CWE-863
RHEL 8 (1 rule)
  • V-251712 The RHEL 8 operating system must not be configured to bypass password requirements for privilege escalation. prevents CWE-863

References