Advisory · CVE-2026-69705
Out-of-bounds write in Windows iSCSI allows unauthenticated code execution
Windows iSCSI has an out-of-bounds write an unauthenticated attacker can trigger over the network to execute code, separate from the other iSCSI flaws in this month's updates. Microsoft rates it CVSS 3.1 9.8.
- Vendor
- Microsoft
- Product
- Windows iSCSI
- Identifier / CWE
- CVE-2026-69705
CWE-787 - Action timing
- Immediate
Explain it like I’m five
The storage connector writes data past the edge of the buffer it was given, and what lands outside becomes the attacker's foothold.
- 01Reach the component
An unauthenticated attacker sends crafted network traffic to a Windows system running Windows iSCSI.
- 02Memory flaw triggers
The component mishandles the input and corrupts or reuses memory outside its intended bounds.
- 03Code runs
The attacker gains code execution in the component's context on the target system.
What happened
Microsoft disclosed CVE-2026-69705 in its October 2026 update guide: an out-of-bounds write (CWE-787) in Windows iSCSI lets an unauthorized attacker execute code over a network.
Microsoft lists the affected Windows releases in its update guide. Apply the October 2026 security updates for your release rather than relying on a version guess here.
What to do
- Inventory every Windows iSCSI deployment, including test, training, and individually managed instances.
- Apply the vendor fix or upgrade exactly as directed in the linked vendor bulletin or advisory.
- Restrict network access to Windows iSCSI while remediation is underway, especially for internet-facing instances.
- Review application and server logs for iSCSI crashes or storage drops, and connection attempts from networks that should not reach storage.
- Check for accounts, content, or configuration created outside normal change processes, and rotate exposed credentials where access cannot be ruled out.
- Verify the deployed version or patch level after remediation.
Management note
Three iSCSI flaws in one month underline how much trust storage traffic gets. Patch and segment the storage network.