CVE-2026-93853

Barman snapshot backup deletion trusts unverified backup catalog metadata

Published Sep 29, 2026 CVSS 4.0 · 7.2 High EPSS < 1% KEV · Not listed
Description
Unverified ownership in Barman snapshot backup deletion allows a principal who can write the backup catalog to cause Barman to delete unrelated cloud snapshots. When a snapshot backup is deleted, either explicitly or by retention policy enforcement, Barman reads the snapshot identifiers from the backup.info file and passes them to the cloud provider's delete API using Barman's own credentials, without verifying that the snapshots belong to that backup. An attacker who can overwrite backup.info but lacks snapshot delete permissions can substitute the identifiers of other snapshots, causing Barman to delete any snapshot its cloud identity can reach on AWS, Microsoft Azure, or Google Cloud. Exploitation requires a deployment where the principal that writes the backup catalog is separate from the identity Barman uses to delete snapshots. Barman versions from 3.4.0 (Google Cloud), 3.6.0 (Azure), and 3.7.0 (AWS) up to and including 3.20.0 are affected. The issue is fixed in Barman 3.20.1.

Remediation

Vendor Solution

Upgrade to Barman 3.20.1 or later. Before deleting a snapshot, Barman now reads the snapshot name from the cloud provider and refuses the deletion unless it matches the backup being deleted.


Vendor Workaround

Restrict write access to the backup catalog in object storage to the identity Barman uses. Enable object versioning or object lock on the backup bucket, and on AWS use EBS Snapshot Lock (aws_snapshot_lock_mode) to protect snapshots from deletion.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Enterprisedb
Enterprisedb barman
Vendors & Products Enterprisedb
Enterprisedb barman
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description Unverified ownership in Barman snapshot backup deletion allows a principal who can write the backup catalog to cause Barman to delete unrelated cloud snapshots. When a snapshot backup is deleted, either explicitly or by retention policy enforcement, Barman reads the snapshot identifiers from the backup.info file and passes them to the cloud provider's delete API using Barman's own credentials, without verifying that the snapshots belong to that backup. An attacker who can overwrite backup.info but lacks snapshot delete permissions can substitute the identifiers of other snapshots, causing Barman to delete any snapshot its cloud identity can reach on AWS, Microsoft Azure, or Google Cloud. Exploitation requires a deployment where the principal that writes the backup catalog is separate from the identity Barman uses to delete snapshots. Barman versions from 3.4.0 (Google Cloud), 3.6.0 (Azure), and 3.7.0 (AWS) up to and including 3.20.0 are affected. The issue is fixed in Barman 3.20.1.
Title Barman snapshot backup deletion trusts unverified backup catalog metadata
Weaknesses CWE-283
References
Metrics cvssV4_0

{'score': 7.2, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:H/SC:N/SI:H/SA:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
EDB
Published
Updated
Sep 30, 2026, 3:28 PM
Reserved
Sep 18, 2026, 6:52 PM
Status
Deferred
Published
Sep 29, 2026, 9:19 PM
Modified
Sep 30, 2026, 7:57 PM