CVE-2026-85817 — Microsoft
HIGHCVE-2026-85817 is a high-severity (CVSS 8.8) CWE-807 vulnerability. No vendor fix is recorded yet; mitigation options are listed below.
Reliance on untrusted inputs in a security decision in Windows PowerShell allows an unauthorized attacker to execute code over a network.
Exploitation Status
No confirmed exploitation observed yet
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-85817.
Description
Reliance on untrusted inputs in a security decision in Windows PowerShell allows an unauthorized attacker to execute code over a network.
Detection & mitigation playbook
VulnerabilityDetect
Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`).
Remediation status
No fixed release is recorded for CVE-2026-85817 yet. Track the upstream advisory, and apply the exposure-reduction steps below in the meantime.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
Frequently Asked Questions
Is CVE-2026-85817 in your dependencies?
Find it across , including transitive dependencies.