CVE-2026-11858
Missing authorization in Quanos SCHEMA ST4 Client Update Service allows arbitrary file overwrite as SYSTEM
02 Description
Missing authorization in Quanos SCHEMA ST4 Client Update Service allows arbitrary file overwrite as SYSTEM
03 Exploitation and scoring
- Exploitation
- Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.
- SSVC decision
- ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
- AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
- Technical ImpacttotalSuccessful exploitation gives total control of the vulnerable component.
- EPSS probability
- 0.12% probability of exploitation activity in the next 30 days.
- EPSS percentile
- Equal to or higher than the score of 1.9% of scored records. A rank, not a probability.
- NVD base score
- 8.4 (CVSS v4.0), scored by the NVD independently of the CNA.
- NVD CVSS vector
- CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- NVD analysis status
- Deferred. NVD last modified this record on 2026-10-26.
- Red Hat severity
- No Red Hat rating. Red Hat rates the CVEs that affect its products.
Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.
04 Metadata
- Published
- 2026-06-17 11:50Z4 MO AGO
- Last updated
- 2026-06-17 14:56Z4 MO AGO
- Reserved
- 2026-06-10
- Assigning CNA
- SEC-VLab
- Record state
- PUBLISHED
- Severity
- High (CVSS 8.4)
- CNA CVSS vector
- CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
- Weaknesses
- CWE-862Missing AuthorizationClass
- Data version
- 5.2
- Document digest
- 3680259f55636dce33e1e61e64674c8b11f0896684daf05dc7adefffb78852e7
05 Affected products
06 References
- r.sec-consult.comhttps://r.sec-consult.com/quanos
07 Remediation
The vendor does not provide a patch. The vendor recommends disabling the affected Client Update Service. Updating the client is then only possible manually with a privileged user account. Quanos confirms that exploitation requires local host access with an authenticated user session. In properly managed environments following the Least Privilege principle, the attack surface is significantly reduced. Quanos Cloud/SaaS deployments are not affected. Quanos considers the migration to the Cloud/SaaS architecture the strategic long-term solution.