CVE-2026-27965: Vitess users with backup storage access can gain unauthorized access to production deployment environments
Impact
Any user with read/write access to the backup storage location (e.g. an S3 bucket) can manipulate backup manifest files so that arbitrary code is later executed when that backup is restored. This can be used to provide that attacker with unintended/unauthorized access to the production deployment environment — allowing them to access information available in that environment as well as run any additional arbitrary commands there.
Patches Fixes are expected to be released with versions v23.0.3 and v22.0.4 See fix commit at https://github.com/vitessio/vitess/commit/4c0173293907af9cb942a6683c465c3f1e9fdb5c
Workarounds
If maintainers intended to use an external decompressor then they can always specify that decompressor command in the --external-decompressor flag value for vttablet and vtbackup. That then overrides any value specified in the manifest file.
If maintainers did not intend to use an external decompressor, nor an internal one, then they can specify a value such as cat or tee in the --external-decompressor flag value for vttablet and vtbackup to ensure that a harmless command is always used.
References
Users can read more about the issue here: https://github.com/vitessio/vitess/issues/19459
Other sources
Vitess is a database clustering system for horizontal scaling of MySQL. Prior to versions 23.0.3 and 22.0.4, anyone with read/write access to the backup storage location (e.g. an S3 bucket) can manipulate backup manifest files so that arbitrary code is later executed when that backup is restored. This can be used to provide that attacker with unintended/unauthorized access to the production deployment environment — allowing them to access information available in that environment as well as run any additional arbitrary commands there. Versions 23.0.3 and 22.0.4 contain a patch. Some workarounds are available. Those who intended to use an external decompressor then can always specify that decompressor command in the --external-decompressor flag value for vttablet and vtbackup. That then overrides any value specified in the manifest file. Those who did not intend to use an external decompressor, nor an internal one, can specify a value such as cat or tee in the --external-decompressor flag value for vttablet and vtbackup to ensure that a harmless command is always used.
— MITRE
Vitess users with backup storage access can gain unauthorized access to production deployment environments
— Microsoft
Affected Software
Remediation
Patch Available
Event History
Frequently Asked Questions
What is the vulnerability severity of CVE-2026-27965?
CVE-2026-27965 is considered to be of high severity due to the potential for unauthorized access to production environments.
How do I fix CVE-2026-27965?
To fix CVE-2026-27965, upgrade to Vitess versions 23.0.3 or 22.0.4 or later.
What are the potential impacts of CVE-2026-27965?
The potential impacts of CVE-2026-27965 include unauthorized access and manipulation of production deployment environments.
Who is affected by CVE-2026-27965?
CVE-2026-27965 affects all Vitess users with read/write access to the backup storage location before the mentioned fixed versions.
What kind of storage is involved in CVE-2026-27965?
CVE-2026-27965 involves backup storage locations, such as S3 buckets used by Vitess users.