CVE-2026-15925: Snowflake Python Connector TLS Flaw

CVE-2026-15925 Overview

CVE-2026-15925 is an improper certificate validation vulnerability [CWE-297] affecting the Snowflake Connector for Python. Versions prior to 4.7.1 and 3.18.1 fail to verify that the TLS certificate presented by the server matches the requested hostname. A network-positioned attacker can present any certificate signed by a trusted certificate authority (CA) for any domain, and the connector will accept the connection. Successful exploitation can expose Snowflake credentials, query data, and staged file contents. An attacker can also issue arbitrary SQL within the victim's authenticated connector session, bounded by the affected Snowflake role's privileges.

Critical Impact
On-path attackers can intercept Snowflake connector traffic, steal credentials, and execute arbitrary SQL under the victim's role.

Affected Products

Snowflake Connector for Python versions prior to 4.7.1 (4.x branch)
Snowflake Connector for Python versions prior to 3.18.1 (3.x branch)
Any Python application, ETL job, or data pipeline linking against the vulnerable connector

Discovery Timeline

2026-07-16 - CVE-2026-15925 published to NVD
2026-07-16 - Last updated in NVD database

Technical Details for CVE-2026-15925

Vulnerability Analysis

The Snowflake Connector for Python establishes HTTPS connections to Snowflake endpoints to execute SQL, upload data, and stream results. TLS handshakes on these connections do not enforce hostname verification against the Subject or Subject Alternative Name (SAN) fields of the presented X.509 certificate. As a result, the connector treats any certificate chained to a trusted CA as valid, regardless of which hostname it was issued for.

This breaks the fundamental identity assurance that TLS provides. An attacker who can obtain or reuse any legitimate CA-signed certificate, including one issued for an attacker-controlled domain, can impersonate *.snowflakecomputing.com endpoints. The connector transmits authentication material, query payloads, and staged file contents over the compromised channel.

Root Cause

The defect is classified as CWE-297: Improper Validation of Certificate with Host Mismatch. The connector's HTTPS client validates the certificate chain against the trusted CA store but omits the hostname comparison step. This gap allows any valid leaf certificate to satisfy validation for any target host.

Attack Vector

Exploitation requires an on-path traffic interception capability. Viable positions include Address Resolution Protocol (ARP) or Domain Name System (DNS) poisoning on a local network, rogue Wi-Fi access points, Border Gateway Protocol (BGP) hijacking, and malicious proxies or Tor exit nodes. Once positioned, the attacker redirects the connector's traffic to an attacker-controlled TLS terminator that serves a valid CA-signed certificate for any domain. The connector completes the handshake, sends Snowflake credentials or OAuth tokens, and executes queries through the attacker. The attacker can passively capture credentials and data or actively rewrite SQL statements issued during the session.

No verified public exploit code is available at this time. See the GitHub Release v4.7.1 and GitHub Release v3.18.1 for fix details.

Detection Methods for CVE-2026-15925

Indicators of Compromise

Snowflake sessions originating from unexpected source IP addresses or geographies for a given service account.
Unusual QUERY_HISTORY entries containing SQL that does not match known application patterns, particularly SELECT statements against sensitive tables or COPY INTO operations to unfamiliar stages.
Connector processes making outbound HTTPS connections to non-Snowflake IP ranges resolved from *.snowflakecomputing.com hostnames.

Detection Strategies

Inventory Python environments and identify installations of snowflake-connector-python at versions below 4.7.1 or 3.18.1 using pip list or software bill of materials (SBOM) tooling.
Compare DNS resolutions for *.snowflakecomputing.com against Snowflake's published IP ranges and alert on deviations.
Correlate Snowflake LOGIN_HISTORY and SESSIONS views with expected client IPs and user agents; investigate mismatches.

Monitoring Recommendations

Enable Snowflake network policies to restrict logins to known corporate egress IPs, reducing the value of stolen credentials.
Monitor for TLS connections to Snowflake endpoints presenting certificates not chained to Snowflake's expected issuer.
Log and review outbound proxy traffic from hosts running Snowflake data pipelines for unexpected destinations.

How to Mitigate CVE-2026-15925

Immediate Actions Required

Upgrade snowflake-connector-python to version 4.7.1 (4.x branch) or 3.18.1 (3.x branch) across all systems. Upgrades must be performed manually.
Rotate Snowflake credentials, key pairs, and OAuth tokens used by any application that ran the vulnerable connector on untrusted networks.
Audit QUERY_HISTORY, LOGIN_HISTORY, and stage access logs for suspicious activity dating back to the earliest possible exposure.

Patch Information

Snowflake fixed the hostname verification defect in the Snowflake Connector for Python 4.7.1 release and the 3.18.1 release. Users must manually upgrade; there is no automatic remediation path.

Workarounds

Restrict Snowflake connector traffic to trusted networks and require a corporate VPN or private connectivity such as AWS PrivateLink or Azure Private Link until patching is complete.
Apply Snowflake network policies that whitelist only known egress IPs for service accounts and human users.
Enforce least-privilege Snowflake roles so that any compromised session has minimal data access and no administrative rights.

bash

# Upgrade the Snowflake Connector for Python to a patched version
pip install --upgrade "snowflake-connector-python>=4.7.1"

# Or, for environments pinned to the 3.x branch
pip install --upgrade "snowflake-connector-python>=3.18.1,<4.0.0"

# Verify the installed version
python -c "import snowflake.connector; print(snowflake.connector.__version__)"