CVE-2025-26399
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.
do firstApply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Can a WAF block it? Partly. Insecure deserialization payloads can be built from many different gadget chains, so WAF signatures only catch the known ones.
Also consider: allow-list classes · patch
Based on the weakness type only; no CVE-specific evidence yet. We check Cloudflare, AWS, Google Cloud Armor and Azure; for Akamai, Imperva, Fastly, F5, ask your vendor.
Is CVE-2025-26399 being exploited?
Yes. CVE-2025-26399 appears in CISA's Known Exploited Vulnerabilities catalog, which means exploitation in the wild has been confirmed and reported. Treat it as active rather than theoretical, and patch it ahead of higher-scoring vulnerabilities that carry no exploitation evidence.
How severe is CVE-2025-26399?
CVE-2025-26399 is rated Critical with a CVSS score of 9.8. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2025-26399?
Yes. A fix has been recorded for CVE-2025-26399. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2025-26399 affect?
CVE-2025-26399 affects solarwinds:web_help_desk. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
- affected12.8.7 and below
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.
public exploits
Unvetted proof-of-concept code on GitHub: 1 GitHub proof of concept · 1 Nuclei template
- SolarWinds Web Help Desk < 12.8.7 - AjaxProxy Deserialization RCE · detection template · critical
- rxerium/CVE-2025-26399 · 2 ★
Listed so you can judge urgency, not as a recommendation to run anything. GitHub “proofs of concept” are unvetted: some are fake or carry malware. Exploit-DB marks the entries its staff verified.
cisa ssvc
- exploitation
- active
- automatable
- yes
- technical impact
- total
Assessed by CISA 23 Sept 2025 (SSVC 2.0.3).
timeline
- 23 Sept 2025First proof-of-concept repository on GitHub (unvetted)
- 23 Sept 2025CISA SSVC assessment: exploitation active · same day later
- 23 Sept 2025Published · same day later
- 9 Mar 2026Added to CISA KEV (exploited in the wild) · 167 days (about 6 months) later
- 12 Mar 2026CISA remediation due date (US federal agencies) · 3 days later
- 4 Aug 2026CVE record last updated · 145 days (about 5 months) later
- 2 Nov 2026Analysed by vulneraibility.com · 91 days (about 3 months) later
- Advisorymicrosoft.com /en-us/security/blog/2026/02/06/active-exploitation-solarwinds-web-help-desk/
- Linksolarwinds.com /trust-center/security-advisories/CVE-2025-26399
- Linkdocumentation.solarwinds.com /en/success_center/whd/content/release_notes/whd_12-8-7-hotfix-1_release_notes.h
- Linkcisa.gov /known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-26399
sources
- CVE List (CVE.org): description, affected versions, references; CVE Terms of Use
- NVD: CVSS and CPE data
- CISA KEV catalog: exploitation, date added, due date
- CISA Vulnrichment (ADP): SSVC decision points
- FIRST EPSS: exploit probability and percentile
- Nuclei templates: detection templates
- PoC-in-GitHub: GitHub repositories that claim a proof of concept
- Summary, impact and triage tags: written by our AI analysis pipeline from the sources above. Check them against the sources.