Cyber Resilience

CVE-2025-40551

RCE in Solarwinds Web Help Desk ≤ 2026.1

CISA KEVActive ExploitationEUVD ExploitedRCEDeserialization
Published
28 January 2026
Modified
03 February 2026
Patch / advisory
CVSS Score v3.1 9.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.84 99.7th percentile
Risk Priority 97 floored blend · peak EPSS

Summary

CVE-2025-40551 is a critical-severity Deserialization of Untrusted Data (CWE-502) vulnerability in Solarwinds Web Help Desk. Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 0.3% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog.

The strongest mitigations our analysis identified map to SI-10 (Information Input Validation) and SI-2 (Flaw Remediation) — 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-2025-40551 is an untrusted data deserialization vulnerability (CWE-502) affecting SolarWinds Web Help Desk. Published on January 28, 2026, it enables remote code execution (RCE), allowing attackers to run arbitrary commands on the host machine. The vulnerability carries a CVSS v3.1 base score of 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H), indicating critical severity due to its high impact on confidentiality, integrity, and availability.

Unauthenticated remote attackers can exploit this vulnerability over the network with low complexity and no user interaction required. Successful exploitation grants full control over the affected host, potentially leading to complete system compromise, data theft, or further lateral movement within the environment.

SolarWinds has published mitigation details in their security advisory at https://www.solarwinds.com/trust-center/security-advisories/CVE-2025-40551 and Web Help Desk 2026.1 release notes at https://documentation.solarwinds.com/en/success_center/whd/content/release_notes/whd_2026-1_release_notes.htm, which include patches addressing the issue. The vulnerability is also listed in CISA's Known Exploited Vulnerabilities Catalog at https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-40551, urging federal agencies to apply mitigations promptly.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

SolarWinds Web Help Desk was found to be susceptible to an untrusted data deserialization vulnerability that could lead to remote code execution, which would allow an attacker to run commands on the host machine. This could be exploited without authentication.

CWE(s)
KEV Date Added
See CISA KEV catalog

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

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.
Why these techniques?

Untrusted data deserialization vulnerability in SolarWinds Web Help Desk enables unauthenticated remote code execution over the network in a public-facing web application, directly mapping to T1190: Exploit Public-Facing Application.

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

Likely ATT&CK TechniquesAI

Techniques this vulnerability likely enables, inferred from its description, weakness type, and attributed-actor tradecraft. Confidence is per-technique.

T1190 Exploit Public-Facing Application Initial Accessconfidence: HIGH
Unauthenticated network deserialization flaw directly enables remote code execution against a public-facing web application.
T1059 Command and Scripting Interpreter Executionconfidence: HIGH
Successful exploitation results in arbitrary command execution on the host OS.
T1068 Exploitation for Privilege Escalation Privilege Escalationconfidence: HIGH
RCE achieved without authentication yields privilege escalation to the process context (typically SYSTEM or root).
inferred from description + CWE · MITRE ATT&CK Enterprise v19.0

CVEs Like This One

CVE-2025-26399Same product: Solarwinds Web Help Deskboth on KEV
CVE-2025-40536Same product: Solarwinds Web Help Deskboth on KEV
CVE-2024-28986Same product: Solarwinds Web Help Deskboth on KEV
CVE-2025-40553Same product: Solarwinds Web Help Desk
CVE-2024-28988Same product: Solarwinds Web Help Desk
CVE-2024-28987Same product: Solarwinds Web Help Deskboth on KEV
CVE-2025-40552Same product: Solarwinds Web Help Desk
CVE-2025-40554Same product: Solarwinds Web Help Desk
CVE-2026-28299Same product: Solarwinds Web Help Desk
CVE-2024-45709Same product: Solarwinds Web Help Desk

Affected Assets

solarwinds
web help desk
≤ 2026.1

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)
  • SI-2 Flaw Remediation
  • SI-10 Information Input Validation
Detect
Catch it (NIST detect / respond)
  • RA-5 Vulnerability Monitoring and Scanning
Harden
Shrink the surface (DISA STIG)

Validate
Prove the fix (OWASP ASVS)

Mitigating Controls (NIST 800-53 r5) AI

prevent

SI-2 mandates timely identification, reporting, and correction of software flaws like this untrusted deserialization vulnerability through vendor patches such as SolarWinds Web Help Desk 2026.1.

prevent

SI-10 requires validation of input format, type, and content, directly preventing exploitation of untrusted data deserialization by rejecting malicious payloads.

detect

RA-5 ensures vulnerability scanning identifies critical issues like CVE-2025-40551 in SolarWinds Web Help Desk, enabling prioritization for remediation.

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-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.

detects

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

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.

detects

Regular scanning of third-party libraries and timely patching reduce the likelihood that unsafe deserialization vulnerabilities remain active.

none

Mandatory malware scanning of data received over networks or storage media intercepts malicious serialized payloads before they are deserialized by the target application.

References