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TI-2026-81409 Aliases CVE-2026-106078GHSA-2749-r626-88hf

Authentication bypass in Veeam Backup for Microsoft 365 REST API

Priority LOW 30CWE-347Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Security bypass
Confidentiality · integrity · availability
Low · None · None
Fix status
No fix listed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-347.

Summary

Veeam Backup for Microsoft 365 from 8.0 through 8.6.0.1102 is affected. The REST API does not properly verify the cryptographic signature of federation tokens (CWE-347). An unauthenticated remote attacker can forge a federation token to bypass REST API authentication and receive responses from endpoints that do not call the backup service.

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

Description from the CNA

A vulnerability allowing an unauthenticated attacker to bypass REST API authentication with a forged federation token and receive responses from REST API endpoints that do not call the Veeam Backup for Microsoft 365 backup service.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00261 17th 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-2026-106078
  2. 2026-10-27 Alias added: GHSA-2749-r626-88hf
  3. 2026-10-28 Priority changed: MEDIUM → LOW
  4. 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