Microsoft Windows iSCSI: Remote code execution via invalid pointer reference
Summary
The Windows iSCSI component of Windows Server 2016, 2019, 2022 and 2025 contains a flaw where an invalid pointer or reference is released (CWE-763). According to the CVE description, an unauthorized attacker on the network can execute code without credentials. The CVSS 3.1 base score is 9.8 (critical). The NVD record is still awaiting analysis, and the linked Microsoft advisory could not be verified at the time of writing.
Affected
- Windows Server 2016 and Server Core installation: 10.0.14393.0 to before 10.0.14393.9688
- Windows Server 2019 and Server Core installation: 10.0.17763.0 to before 10.0.17763.9487
- Windows Server 2022: 10.0.20348.0 to before 10.0.20348.5870
- Windows Server 2025 and Server Core installation: 10.0.26100.0 to before 10.0.26100.33822
Fixed in
- Fixed builds are not explicitly stated in the sources. The end of each affected range implies the first fixed build: 10.0.14393.9688 (Server 2016), 10.0.17763.9487 (Server 2019), 10.0.20348.5870 (Server 2022), 10.0.26100.33822 (Server 2025).
- KB numbers: Unknown.
Workaround
- Unknown from the vendor advisory.
- General hardening for iSCSI (not taken from this CVE's advisory): disable the iSCSI Target Server role if it is not used; restrict TCP port 3260 to the storage network and block it from user networks and the internet.
Exploitation
- CISA SSVC assessment: exploitation none, automatable yes, technical impact total.
- No public reports of exploitation, public proof of concept or CISA KEV listing were found at the time of writing.
Our recommendation
- Confirm the CVE ID and the affected builds on the Microsoft Security Update Guide before making changes.
- Identify all Windows servers with the iSCSI Target Server role and check whether they are reachable from untrusted networks.
- Restrict TCP port 3260 to the storage network and remove any internet exposure.
- Install the Microsoft update for the affected builds as soon as it is confirmed, and restart the servers.
- Monitor CISA KEV and vendor advisories for changes in exploitation status.
Information from Microsoft (Patch Tuesday November 2026)
- Severity (Microsoft)
- Important
- Impact
- Remote code execution – Windows iSCSI
- Status on Patch Tuesday
- Neither exploited nor publicly disclosed
- Exploitability assessment
- Exploitation less likely
- Product family
- Windows, Windows ESU (Extended Security Updates)
- Updates (KB)
- KB5131291, KB5131085, KB5131090, KB5131080, KB5131077
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Microsoft Security Update Guide: CVE-2026-88234 msrc.microsoft.com
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 10 Nov 2026, 20:35.
Original description (NVD)
Release of invalid pointer or reference in Windows iSCSI allows an unauthorized attacker to execute code over a network.
NVD references (1)
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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