What is CVE-2025-40553?
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.
The record classifies CVE-2025-40553 under weakness class CWE-502. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on confidentiality, integrity, availability. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 281 days ago.
Severity and exploitation probability
- CVSS v3.1 base score
- 9.8 — CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - EPSS (FIRST)
- 67.9% probability of exploitation in the next 30 days, higher than 99.3% of all scored CVEs
- CISA KEV
- Not listed in the CISA Known Exploited Vulnerabilities catalog
- Threadlinqs priority
- 10/10 — CISA lists it as used in ransomware, which Threadlinqs scores at the maximum
- Published
- 2026-01-28, last modified 2026-02-27
Is CVE-2025-40553 being exploited?
CISA flags the vulnerability as one used in known ransomware campaigns. It currently carries a trending score of 30 in the Threadlinqs vulnerability feed.
Affected products and versions
- Solarwinds: Web Help Desk
How to fix CVE-2025-40553
The record marks a vendor fix as available for CVE-2025-40553. Patch reference: https://www.solarwinds.com/trust-center/security-advisories/cve-2025-40553. Vendor advisory: https://www.solarwinds.com/trust-center/security-advisories/CVE-2025-40553. Apply the vendor fix referenced above to every affected product listed in this record, then confirm the running version against the vendor advisory.
Threat activity tracking CVE-2025-40553
2 tracked threats in the Threadlinqs corpus reference CVE-2025-40553, either in the campaign’s CVE list or as an indicator on the campaign record.
- SolarWinds Web Help Desk Pre-Auth RCE Chain (CVE-2025-40552, CVE-2025-40553, CVE-2025-40554) — CRITICAL · 2026-02-25
- SolarWinds Web Help Desk Deserialization RCE - CISA KEV — CRITICAL · 2026-02-03
Sources
Enriched from CVE.org, FIRST EPSS. Last verified by Threadlinqs on .