Timescale pgvectorscale: Type confusion in DiskANN index handling (CVE-2026-116489)

Timescale pgvectorscale versions prior to 0.9.1 are susceptible to a type confusion vulnerability. The flaw originates from the ability of low-privileged database users to shadow pgvector's vector type or operators. An attacker possessing 'CREATE' privilege on the 'vectorscale' schema can define shadow objects and subsequently execute DiskANN index creation and query operations using malicious values. This leads to out-of-bounds read/write operations within the database process memory.

Impact

Successful exploitation may result in the disclosure of sensitive memory contents, server process crashes leading to denial-of-service, or the escalation of local database privileges by an authenticated user.

Recommendation

• Upgrade the pgvectorscale extension to version 0.9.1 or later to remediate the vulnerability.
• Audit current database user privileges; restrict 'CREATE' permissions on the 'vectorscale' schema to trusted administrative or service accounts.
• Monitor database error logs for repeated segmentation faults or memory-related crashes originating from the pgvectorscale extension.