Microsoft Windows BITS: Local privilege escalation via heap-based buffer overflow
Summary
A heap-based buffer overflow in the Windows Background Intelligent Transfer Service (BITS) allows a locally authorized attacker to elevate privileges. Microsoft states that a successful attacker could gain SYSTEM privileges. The attacker needs local access and low privileges, and the attack is rated as highly complex, so it is not directly reachable from the internet.
Affected
- Windows 10 Version 1607 (10.0.14393.0 to before 10.0.14393.9688)
- Windows 10 Version 1809 (10.0.17763.0 to before 10.0.17763.9487)
- Windows 10 Version 21H2 (10.0.19044.0 to before 10.0.19044.7846)
- Windows 10 Version 22H2 (10.0.19045.0 to before 10.0.19045.7846)
- Windows 11 Version 23H2 (10.0.22631.0 to before 10.0.22631.7711)
- Windows 11 Version 24H2 (10.0.26100.0 to before 10.0.26100.9974)
- Windows 11 Version 25H2 (10.0.26200.0 to before 10.0.26200.9974)
- Windows 11 Version 26H1 (10.0.28000.0 to before 10.0.28000.3501)
- Windows 11 Version 26H2 (10.0.26300.0 to before 10.0.26300.9974)
- 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)
Fixed in
- Install the November 2026 security update from Microsoft for the builds listed above.
- Exact KB numbers: Unknown. Check the MSRC advisory.
Workaround
Unknown.
Exploitation
- Microsoft has not marked the vulnerability as exploited in the wild.
- No public proof of concept found.
- CISA SSVC: exploitation none, automatable no, technical impact total.
Our recommendation
- Patch all affected Windows 10, 11 and Server systems with the November 2026 cumulative update, starting with multi-user systems, terminal servers and file servers.
- Check the MSRC advisory for exact KB numbers per product.
- Review local accounts and restrict unnecessary logon rights.
- Monitor for unexpected SYSTEM-level processes and check NVD and CISA KEV for updates.
Information from Microsoft (Patch Tuesday November 2026)
- Severity (Microsoft)
- Important
- Impact
- Elevation of privilege – Windows Background Intelligent Transfer Service (BITS)
- 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, KB5131096, KB5131090, KB5131087, KB5132061
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Microsoft Security Update Guide: CVE-2026-105554 msrc.microsoft.com
- CVE Record: CVE-2026-105554 www.cve.org
- Rapid7: Patch Tuesday November 2026 www.rapid7.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 11 Nov 2026, 09:37.
Original description (NVD)
Heap-based buffer overflow in Windows Background Intelligent Transfer Service (BITS) allows an authorized attacker to elevate privileges locally.
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.
Affected? We can help.
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