CVE-2026-2303 in Go Driver
Summary
by MITRE • 02/10/2026
The mongo-go-driver repository contains CGo bindings for GSSAPI (Kerberos) authentication on Linux and macOS. The C wrapper implementation contains a heap out-of-bounds read vulnerability due to incorrect assumptions about string termination in the GSSAPI standard. Since GSSAPI buffers are not guaranteed to be null-terminated or have extra padding, this results in reading one byte past the allocated heap buffer.
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Analysis
by VulDB Data Team • 02/11/2026
The vulnerability identified as CVE-2026-2303 resides within the mongo-go-driver repository and specifically targets the CGo bindings designed for GSSAPI (Generic Security Services Application Program Interface) authentication on Linux and macOS platforms. This security flaw manifests in a heap out-of-bounds read condition that stems from improper handling of string termination within the GSSAPI standard implementation. The root cause lies in the C wrapper code's incorrect assumptions regarding buffer management, particularly when dealing with GSSAPI authentication mechanisms that do not guarantee null-termination of buffers or provide adequate padding beyond allocated memory regions.
The technical implementation flaw occurs when the CGo wrapper processes authentication tokens and credential data exchanged during GSSAPI authentication flows. Standard GSSAPI buffers may contain binary data that does not include null terminators, and the implementation fails to account for the possibility that these buffers might not have additional padding bytes to accommodate null termination. When the code attempts to read data from these buffers, it accesses memory locations that extend beyond the originally allocated heap space, resulting in a heap out-of-bounds read condition. This vulnerability is particularly concerning because GSSAPI authentication is commonly used in enterprise environments where MongoDB databases require secure authentication against Kerberos-enabled systems, making the attack surface significant for organizations relying on such authentication mechanisms.
The operational impact of this vulnerability extends beyond simple memory access violations and could potentially enable remote attackers to extract sensitive information from heap memory regions. An attacker who successfully exploits this vulnerability might be able to read authentication tokens, database credentials, or other sensitive data that resides in adjacent memory locations. The out-of-bounds read could also potentially lead to information disclosure or, in more severe scenarios, contribute to further exploitation techniques that might leverage the leaked memory contents to bypass security controls. Given that this affects the MongoDB Go driver's authentication capabilities, any application using this driver for GSSAPI authentication is potentially at risk, particularly in environments where Kerberos authentication is implemented across multiple database access points.
Mitigation strategies for CVE-2026-2303 should prioritize immediate patching of the mongo-go-driver repository to address the heap buffer handling implementation. Organizations should also consider implementing network-level monitoring to detect potential exploitation attempts, particularly around authentication-related traffic patterns that might indicate exploitation of this vulnerability. The fix should ensure that all buffer operations properly account for the lack of guaranteed null termination in GSSAPI buffers and implement bounds checking that does not rely on implicit string termination assumptions. Security teams should also review their authentication configurations to minimize the attack surface and consider alternative authentication methods where appropriate. This vulnerability aligns with CWE-129, which addresses improper validation of array index values, and could potentially map to ATT&CK technique T1566 for credential access through authentication bypass mechanisms that exploit authentication library vulnerabilities. Organizations should also implement comprehensive testing procedures to validate that patched implementations properly handle GSSAPI buffer boundaries without relying on implicit null termination assumptions.