# CVE-2026-121925: Buffer overflow in SAML authentication post-back URL handling in libsnowflakeclient and Snowflake PHP PDO Driver

Status: published. Published: 2026-11-04. Updated: 2026-11-04.

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.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- Snowflake / Snowflake PHP PDO Driver: ≥ 3.2.0; < 4.3.0 (affected, semver). Source: CNA: SNOWFLAKE
- Snowflake / Snowflake Libsnowflakeclient: ≥ 2.1.0; < 2.11.1 (affected, semver). Source: CNA: SNOWFLAKE

## Severity and prioritization

- CVSS 3.1: 6.6 (medium); CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H; source: CNA: SNOWFLAKE

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-121

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://docs.snowflake.com/en/release-notes/clients-drivers/php-pdo-2026#version-430-oct-1-2026 (CNA: SNOWFLAKE)

- https://github.com/snowflakedb/libsnowflakeclient/releases/tag/v2.11.1 (CNA: SNOWFLAKE)

## Provenance

- CNA: SNOWFLAKE: https://www.cve.org/CVERecord?id=CVE-2026-121925; retrieved 2026-11-04; source updated 2026-11-04

Revision: 9d7484180ed2b1b92e94466fab8350711a00621460cd1c35ce26bab3a6bcf4f1

Canonical: https://y2.dev/cve/CVE-2026-121925

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