Public vulnerability disclosure

CVE-2025-64394

CVE-2025-64394

publishedCWE-1386

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.

Technical severity4.3 mediumCVSS 4.0 · CNA: hackerone
Published2026-10-27Source updated 2026-11-04
Collected2026-11-042 attributed sources

Fixes and workarounds

No remediation reported in collected sources.

Missing remediation information is not evidence that no patch exists.

Affected products and versions

Affected products, source version ranges and reporting authorities
ProductVersionsAuthority
Backup for Microsoft 365
Veeam
≥ 8.0; ≤ 8.6.0.1102 (affected, semver)
Other versions: unaffected
CNA: hackerone

Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.

CVSS assessments

CVSS scores, vectors and reporting authorities
Version / scoreVectorAuthority
4.0 / 4.3
medium
CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:A/VC:N/VI:L/VA:H/SC:N/SI:N/SA:NCNA: hackerone

Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

References

For agents and automation

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