Microsoft Windows: Relative path traversal in libarchive
Summary
A relative path traversal vulnerability in the Windows build of libarchive, which is used by the built-in tar.exe utility, allows an unauthenticated attacker to tamper with files over the network. Exploitation requires user interaction, for example opening or extracting a crafted archive. The impact is limited to integrity (CVSS 3.1: 6.5, medium).
Affected
- Windows 10 Version 1809 and Windows Server 2019 (including Server Core): builds before 10.0.17763.9376
- Windows 10 Version 21H2: builds before 10.0.19044.7807
- Windows 10 Version 22H2: builds before 10.0.19045.7807
- Windows 11 Version 23H2: builds before 10.0.22631.7652
- Windows 11 Version 24H2 and 25H2, and Windows 11 Version 26H2: builds before 10.0.26100.9711 (24H2), 10.0.26200.9711 (25H2) and 10.0.26300.9711 (26H2)
- Windows 11 Version 26H1: builds before 10.0.28000.3231
- Windows Server 2022: builds before 10.0.20348.5761
- Windows Server 2025 (including Server Core): builds before 10.0.26100.33650
Fixed in
- Security updates from the October 2026 Patch Tuesday, which raise the builds to the versions listed under affected (per the CNA record; verify on the MSRC advisory before rollout)
Workaround
Unknown.
Exploitation
- CISA SSVC: exploitation none, not automatable, partial technical impact
- No public exploitation reported in the consulted sources
Our recommendation
- Install the October 2026 Windows security updates on all affected systems and verify the build numbers against the MSRC advisory
- Until patched, do not extract archives from untrusted sources with tar.exe
- Prioritise systems that handle external archives or file transfers
- Monitor for unexpected file changes after archive extraction
Information from Microsoft (Patch Tuesday October 2026)
- Severity (Microsoft)
- Important
- Impact
- Tampering – Windows Libarchive
- Status on Patch Tuesday
- Neither exploited nor publicly disclosed
- Exploitability assessment
- Exploitation less likely
- Product family
- Windows, Windows ESU (Extended Security Updates)
- Updates (KB)
- KB5127648, KB5126651, KB5126655, KB5126657, KB5126646, KB5126653
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Microsoft Security Update Guide: CVE-2026-69968 msrc.microsoft.com
- Vulners: CVE List record (CNA) vulners.com
- OpenCVE: CVE-2026-69968 app.opencve.io
- Tenable Nessus plugin 365465 www.tenable.com
- Hive Pro: Four Windows CVEs, October 2026 Patch Tuesday natlawreview.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 5 Nov 2026, 11:24.
Original description (NVD)
Relative path traversal in Windows Libarchive allows an unauthorized attacker to perform tampering 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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