The github.com/sylabs/sif/v2/pkg/integrity package does not verify that the hash algorithm(s) used are cryptographically secure when verifying digital signatures.
Patches
A patch is available in version >= v2.8.1 of the module. Users are encouraged to upgrade.
The patch is commit https://github.com/sylabs/sif/commit/07fb86029a12e3210f6131e065570124605daeaa
Workarounds
Users may independently validate that the hash algorithm(s) used for metadata digest(s) and signature hash are cryptographically secure.