Threats / SolarWinds / CVE-2025-26399
CVE-2025-26399
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-08-10
SolarWinds Web Help Desk vulnerability
SolarWinds Web Help Desk contains a deserialization vulnerability in AjaxProxy allowing remote code execution on affected systems.
Verdict
Today item, not a backlog item.
An attacker can exploit unsafe deserialization of untrusted data in the AjaxProxy component to execute arbitrary commands with the privileges of the Web Help Desk service, potentially compromising the host system.
CISA KEV Yes · 2026-03-095Ransomware use Flagged5EPSS 0.8833 (verify live)6CVSS 9.83CISA SSVC Exploitation: active · Automatable: yes · Impact: total4
01
Is it exploitable?
— the evidence, ranked above the scoreReported exploitation
7 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-03-09), flagged for known ransomware use.
Probability (EPSS)
EPSS 0.8833 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
CVSS 9.8 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H) · Affected: SolarWinds, Web Help Desk. Confirm exact fixed builds in the vendor advisory.CVSS — CNA-assigned (CVE.org), version 3.1, set at disclosure.
Weakness (CWE)
Mapped to CWE-502 Deserialization of Untrusted Data — weakness family: Injection.CWE — CNA-assigned (CVE.org); the weakness class drives how the flaw is exploited.
CISA SSVC (triage disposition)
Exploitation: active · Automatable: yes · Technical Impact: totalCISA's own stakeholder-specific triage inputs, published in the CVE record (CISA Coordinator role). NOTE: this is CISA's three decision points; the final Act/Attend/Track decision also requires a Mission & Well-being input not published here, so no overall decision is asserted.
Currency of the record
CISA added this to its KEV catalog 167 days after the CVE record was published.KEV lag = CISA-KEV dateAdded − CVE.org datePublished; a floor on how long the known-exploited flaw sat in the public record before the federal catalog listed it. Severity/weakness here is CNA- or CISA-assigned (current at disclosure), independent of NVD's analysis backlog.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution not established
No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
I craft a malicious serialized object and send it to the AjaxProxy endpoint.
Business
The organization's Web Help Desk service becomes a pivot point for lateral movement within the network.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I trigger deserialization of my payload, causing arbitrary code execution on the server.
Business
Attackers gain command execution capability within the IT support infrastructure, potentially accessing sensitive customer and employee data.
3
Lateral reach — past segmentation narrative 3
Attacker
I establish persistence and escalate privileges to move deeper into the environment.
Business
The organization faces operational disruption, data breach risk, and potential regulatory compliance violations.
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05
Coverage & confidence
— what we know, and what we don’tEstablished (cited)
Coverage gaps — stated, not hidden
Disclosure & credit2
Catalogued by SolarWindsCNA
Credited with finding itAnonymous working with Trend Micro Zero Day Initiativereporter
Found an error? Propose a correction.
A correction is a cited counter-claim — it must cite a source,
gets reviewed by a second human, and is never auto-applied. See the
correction convention and our identity
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