CVE-2026-16870: Multiple Security Vulnerabilities in Snowflake libsnowflakeclient

Multiple security vulnerabilities in Snowflake libsnowflakeclient versions prior to 2.9.2 could allow remote code execution and credential exfiltration. A stack-based buffer overflow in the file download path could allow remote code execution on a victim host. An attacker could exploit this by uploading a file with a crafted encryption metadata field to a shared internal stage that a victim process later downloads, and impact would be limited to deployments where principals with different privilege levels share the same internal stage. A related out-of-bounds write in the same download path could allow memory corruption with attacker-controlled write primitives. An attacker may exploit this through a crafted initialization vector metadata field on a shared stage, and impact would be limited by the same stage-write precondition. Improper validation of connection parameters could allow an attacker-controlled input to redirect outbound authentication requests — including credentials and tokens — to an attacker-controlled endpoint. Impact is limited to embedding deployments where a lower-privileged principal can influence connection configuration while higher-privileged service credentials are in use. The fix is available in Snowflake libsnowflakeclient version 2.9.2. The Snowflake PHP PDO Driver and Snowflake ODBC Driver embed the affected library; fixes are available in versions 4.1.0 and 3.19.0 respectively. Users must manually upgrade.