CVE-2026-27965

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