How severe is CVE-2025-26399?

CVE-2025-26399 has a CVSS score of 9.8/10, rated CRITICAL. Immediate patching is strongly recommended.

Which packages are affected by CVE-2025-26399?

Affected package information for CVE-2025-26399 is not yet fully mapped. Check the official advisory links for details.

How do I fix CVE-2025-26399?

No fixed version has been published for CVE-2025-26399 yet. Monitor the advisory for updates, apply mitigations recommended by the vendor, and use O3 Security to track when a fix becomes available in your stack.

Is CVE-2025-26399 actively exploited in the wild?

No public exploit code has been indexed for CVE-2025-26399 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2025-26399?

CVE-2025-26399 has an EPSS (Exploit Prediction Scoring System) score of 30.5%, placing it in the 97th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score warrants monitoring and prompt remediation.

Is CVE-2025-26399 in the CISA Known Exploited Vulnerabilities catalog?

Yes. CVE-2025-26399 (SolarWinds Web Help Desk Deserialization of Untrusted Data Vulnerability) was added to CISA's Known Exploited Vulnerabilities (KEV) catalog on 2026-03-09. CISA required all US federal civilian agencies to remediate this vulnerability by 2026-03-12. The required action was: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. Being listed in the KEV catalog is the strongest possible confirmation of active exploitation — treat this as a critical priority.

What type of vulnerability is CVE-2025-26399?

CVE-2025-26399 is classified as Deserialization of Untrusted Data (CWE-502). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

Which products and versions are affected by CVE-2025-26399?

CVE-2025-26399 affects solarwinds web help desk (1 version, e.g. 12.8.7). Check the affected-products list on this page against your deployed version to confirm exposure.

When was CVE-2025-26399 published, and has it been updated?

CVE-2025-26399 was published on September 23, 2025 and was last updated on March 10, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CVE-2025-26399: Web Help Desk Deserialization of Untrusted Data…

EPSS Exploitation Probability

via FIRST.org ↗

30.5%probability of exploitation in next 30 days

Moderate Risk97th percentile+3.78%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Description

SolarWinds Web Help Desk was found to be susceptible to an unauthenticated AjaxProxy deserialization remote code execution vulnerability that, if exploited, would allow an attacker to run commands on the host machine. This vulnerability is a patch bypass of CVE-2024-28988, which in turn is a patch bypass of CVE-2024-28986.

Affected Products

1 product · 2 configurations

Application

web help desksolarwinds

≤ 12.8.6

1 version

12.8.7

Frequently Asked Questions

SolarWinds Web Help Desk was found to be susceptible to an unauthenticated AjaxProxy deserialization remote code execution vulnerability that, if exploited, would allow an attacker to run commands on the host machine. This vulnerability is a patch bypass of CVE-2024-28988, which in turn is a patch bypass of CVE-2024-28986.

O3 Security · Impact-Aware SCA

Is CVE-2025-26399 in your stack?

O3 detects CVE-2025-26399 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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