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TI-2025-43980 Aliases CVE-2025-64394GHSA-9h96-gjgh-c298

Arbitrary file write in Veeam Backup for Microsoft 365 installer

Priority LOW 19CWE-1386Published · Updated

Key facts

Attack vector
Local
Privileges required
Low
User interaction
Active
Attack complexity
Low
Attack requirements
Present
Impact type
—
Confidentiality · integrity · availability
None · Low · High
Fix status
No fix listed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA.

Summary

Veeam Backup for Microsoft 365 from 8.0 through 8.6.0.1102 is affected. A flaw in the installer allows a low-privileged local user to write arbitrary files with SYSTEM privileges during installation, related to insecure handling of Windows junctions or mount points (CWE-1386). A local user with low privileges can use this to escalate privileges or cause denial of service.

Written with Claude Haiku 5.5 from the sources below · 2026-11-04

Description from the CNA

A vulnerability allowing a low-privileged local user to write arbitrary files with SYSTEM privileges during the installation of Veeam Backup for Microsoft 365, which can lead to privilege escalation or denial of service.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00107 1st percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
VeeamBackup for Microsoft 3658.0 – 8.6.0.1102—No fix listedCNA
  • Backup for Microsoft 365 VendorVeeam Affected 8.0 – 8.6.0.1102 Fixed in — No fix listed CNA

Remediation

The sources list no fixed version for Veeam Backup for Microsoft 365.

Written with Claude Haiku 5.5 from the sources below · 2026-11-04

Timeline

  1. 2026-10-27 Threatist record created from CVE-2025-64394
  2. 2026-10-27 Alias added: GHSA-9h96-gjgh-c298
  3. 2026-11-04 CISA SSVC decision points changed

References

Other 1

  • TI-2024-27107 Deserialization of untrusted data in Veeam Backup and Recovery KEVCVSS 3.1CRITICAL 9.8
  • TI-2022-09844 Veeam Backup & Replication 10.x and 11.x has Incorrect Access Control (issue 1 of 2). KEVCVSS 3.1CRITICAL 9.8
  • TI-2022-09843 Improper limitation of path names in Veeam Backup & Replication 9.5U3, 9.5U4,10.x, and… KEVCVSS 3.1HIGH 8.8
  • TI-2023-12256 Missing authentication in Veeam Backup & Replication KEVCVSS 3.1HIGH 7.5
  • TI-2020-08796 Deserialization of untrusted data in Veeam One Agent CVSS 3.1CRITICAL 9.8
  • TI-2024-19623 Veeam Backup Enterprise Manager allows unauthenticated users to log in as any user to enterprise manager web interface. CVSS 3.0CRITICAL 9.8
See all 119 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences