Cyber Resilience

CVE-2026-58127

RCE in Hyland Pacsgear ≤ 5.2.1

Published
01 July 2026
Modified
09 July 2026
Patch / advisory
CVSS Score v4 9.3
Click a component to see what it means
Raw vectorCVSS:4.0/AV:N/AC:L/AT:N/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 0.013 67th percentile
Risk Priority 48 floored blend · peak EPSS

Summary

CVE-2026-58127 is a critical-severity Missing Authentication for Critical Function (CWE-306) vulnerability in Hyland Pacsgear. Its CVSS base score is 9.3 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 33% of CVEs by exploit likelihood; 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 AC-14 (Permitted Actions Without Identification or Authentication) and IA-2 (Identification and Authentication (Organizational Users)) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

PACSgear MediaWriter 5.2.1 exposes a .NET Remoting TCP service on port 9000 via PacsgearMediaServerEngine.dll, registered with ObjectURIs RemoteObj and UIRemoteObj, without any authentication requirement. By exploiting the MarshalByRefObject object unmarshalling technique and implementing .NET WebClient class methods, an unauthenticated remote…

more

attacker can read and write arbitrary files on the host filesystem. The ObjectURIs are identical across all installations by default. Chaining the arbitrary file write primitive with DLL hijacking opportunities in the MediaWriter service (which runs as NT Authority\\SYSTEM and loads missing DLLs such as CRYPTBASE.DLL from the application directory) enables unauthenticated remote code execution as SYSTEM upon service restart.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

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.
T1133 External Remote Services Persistence
Adversaries may leverage external-facing remote services to initially access and/or persist within a network.
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-58126Same product: Hyland Pacsgear
CVE-2023-21839Shared CWE-306, CWE-502
CVE-2026-26333Shared CWE-306, CWE-502
CVE-2026-12046Shared CWE-306, CWE-502
CVE-2025-34414Shared CWE-306, CWE-502
CVE-2025-35050Shared CWE-306, CWE-502
CVE-2026-25550Shared CWE-306, CWE-502
CVE-2026-23746Shared CWE-306, CWE-502
CVE-2025-35051Shared CWE-306, CWE-502
CVE-2024-3301Shared CWE-502

Affected Assets

hyland
pacsgear
≤ 5.2.1

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)
  • 6 hardening rules · 3 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V6.2.3
  • V6.4.4
  • V10.4.16
  • V12.1.3

Mitigating Controls (NIST 800-53 r5) AI

Directly mandates unique identification and authentication of users before access to functions requiring identity.

Extends the same authentication requirement to non-organizational users accessing critical functionality.

Requires authentication of services before they can invoke or expose critical functions.

Explicitly identifies and limits actions permitted without authentication, preventing critical functions from being exposed.

Developer testing and evaluation can uncover deserialization flaws before deployment.

Input validation directly stops deserialization of untrusted data by ensuring inputs are valid before processing.

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-03 full match
prevents

Directly requires authentication of users/services/hardware, which eliminates missing authentication for critical functions.

PR.AA-01 partial match
prevents

Managing identities and credentials is a prerequisite for authentication but does not itself enforce it on critical functions.

PR.AA-05 partial match
prevents

Defining and enforcing authorizations assumes prior authentication and therefore only partially mitigates the absence of authentication.

PR.IR-01 partial match
prevents

Protecting networks from unauthorized access can be undermined by missing authentication but does not address the root authentication gap.

PR.PS-02 none match
prevents

PR.PS-02 addresses only post-deployment updates/patching and cannot prevent introduction of unsafe deserialization code, yet it can remediate some instances when the flaw exists in outdated libraries or components.

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

The control explicitly calls for authentication before any critical function is reached, eliminating the possibility of bypassing authentication for high-value operations.

finds

Security testing includes validation of deserialization routines and the use of untrusted data, reducing the likelihood that unsafe object reconstruction will be deployed.

prevents

Mandating authentication requirements for critical functions at the requirements-gathering stage ensures that essential operations are not left unprotected by missing login or verification mechanisms.

mitigates

Mandating authentication for network services and critical functions stops attackers from invoking sensitive operations without credentials, closing gaps where authentication is absent for important capabilities.

prevents

Security engineering principles insist on authentication and authorization for every critical function, eliminating entry points that lack any access control mechanism.

prevents

Requiring vetted libraries, regular updates and SAST before release reduces the likelihood that deserialization logic will accept and act on attacker-controlled serialized objects.

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` (authoritative rows only; rows rated `none` are excluded).

Oracle Linux 8 (2 rules)
  • V-248585 OL 8 must require reauthentication when using the "sudo" command. prevents CWE-306
  • V-248827 OL 8 must not have the rsh-server package installed. prevents CWE-306
RHEL 7 (2 rules)
  • V-204442 The Red Hat Enterprise Linux operating system must not have the rsh-server package installed. prevents CWE-306
  • V-237635 The Red Hat Enterprise Linux operating system must require re-authentication when using the "sudo" command. prevents CWE-306
RHEL 8 (2 rules)
  • V-230492 RHEL 8 must not have the rsh-server package installed. prevents CWE-306
  • V-237643 RHEL 8 must require re-authentication when using the "sudo" command. prevents CWE-306

References