CVE-2026-121925 in Libsnowflakeclient
Summary
by MITRE • 11/04/2026
A stack-based buffer overflow in libsnowflakeclient and the Snowflake PHP PDO Driver could, under specific conditions, result in memory corruption during SAML-based authentication. During a native SSO/SAML login flow, the affected drivers may have copied a value taken from the identity provider's HTML response into a fixed-size memory buffer without first validating the length of that value. An attacker who controlled or had compromised the configured identity provider — or who was able to redirect the SAML single sign-on endpoint to an attacker-controlled server — might have leveraged this by returning an oversized response, potentially resulting in a crash or, in specific circumstances, remote code execution within the context of the application running the library. The fix is available in libsnowflakeclient version 2.11.1 and Snowflake PHP PDO Driver version 4.3.0. Users must manually upgrade.
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Analysis
by VulDB Data Team • 11/04/2026
The vulnerability identified involves a critical stack-based buffer overflow within the libsnowflakeclient library and the associated Snowflake PHP PDO Driver, specifically affecting the SAML-based authentication workflow. This flaw stems from an improper boundary check during the processing of identity provider responses in native single sign-on scenarios. When the application initiates a login flow, it receives data from the external identity provider's HTML response. The affected software components fail to validate the length of specific values extracted from this response before attempting to copy them into fixed-size memory buffers on the stack. This lack of input validation allows an oversized payload to be written beyond the allocated buffer boundaries, leading directly to memory corruption and potential control flow hijacking.
From a technical perspective, this issue is classified under CWE-121, which denotes a stack-based buffer overflow resulting from copying data without adequate bounds checking. The operational impact is severe because it occurs during an authentication phase that typically involves network communication with external entities. An attacker who has compromised the configured identity provider or can redirect the SAML single sign-on endpoint to a malicious server can craft a specially crafted response containing an oversized value. Upon receiving this malformed data, the vulnerable driver attempts to copy it into the stack buffer without verifying its size relative to the buffer capacity. This action overwrites adjacent memory locations on the call stack, which may include return addresses or function pointers.
The exploitation of this vulnerability can lead to a denial of service through application crashes if the memory corruption causes an immediate fault. However, under specific conditions where the attacker has sufficient control over the overwritten data and the surrounding memory layout, it is possible to achieve remote code execution within the context of the process running the library. This represents a significant security risk as it allows unauthorized access or full compromise of the system hosting the Snowflake client application. The attack vector aligns with ATT&CK techniques related to input validation failures and potentially command injection if the overwritten memory leads to arbitrary code execution paths.
Mitigation requires immediate manual intervention by upgrading the affected components to patched versions that include proper length validation before buffer copying operations. Specifically, users must upgrade libsnowflakeclient to version 2.11.1 or later and the Snowflake PHP PDO Driver to version 4.3.0 or higher. These updates implement strict checks on incoming data sizes from identity providers to ensure they fit within allocated buffers. In addition to upgrading software organizations should enforce rigorous input validation policies for all external authentication responses and consider implementing defense-in-depth strategies such as stack canaries, address space layout randomization, and restricted execution permissions to mitigate the impact of potential buffer overflow exploits in legacy or unpatched systems.