CVE-2017-8816 in macOS
Summary
by MITRE
The NTLM authentication feature in curl and libcurl before 7.57.0 on 32-bit platforms allows attackers to cause a denial of service (integer overflow and resultant buffer overflow, and application crash) or possibly have unspecified other impact via vectors involving long user and password fields.
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Analysis
by VulDB Data Team • 04/16/2026
The vulnerability identified as CVE-2017-8816 affects the NTLM authentication implementation within curl and libcurl libraries versions prior to 7.57.0, specifically on 32-bit platforms. This issue stems from inadequate input validation and handling of authentication credentials during the NTLM authentication process. The flaw manifests when attackers provide excessively long user and password fields, which triggers integer overflow conditions that ultimately lead to buffer overflow scenarios within the application memory space. The vulnerability is particularly concerning because it can be exploited to cause application crashes or potentially enable more severe impacts depending on the execution environment.
The technical root cause of this vulnerability lies in the way curl and libcurl handle authentication credential lengths during NTLM authentication negotiations. When processing user and password inputs, the software performs calculations that can exceed the maximum value representable by 32-bit signed integers, resulting in integer overflow conditions. This overflow subsequently affects buffer allocation calculations, leading to insufficiently sized buffers that cannot accommodate the full credential data. The CWE-190 classification applies directly to this issue as it represents an integer overflow vulnerability that leads to buffer overflow conditions. The vulnerability specifically impacts 32-bit platforms due to the limited address space and integer size constraints inherent to these architectures, making them more susceptible to arithmetic overflow conditions.
The operational impact of CVE-2017-8816 extends beyond simple denial of service scenarios to potentially encompass more serious security implications. While the primary effect is application crash and denial of service, the buffer overflow conditions could theoretically be exploited to execute arbitrary code if proper memory protections are not in place. Attackers could leverage this vulnerability to disrupt services by causing applications using curl or libcurl to crash, effectively preventing legitimate users from accessing services that depend on these libraries. In environments where curl is used for automated processes or critical infrastructure components, this vulnerability could lead to significant service interruptions and operational downtime. The vulnerability affects any application that relies on curl or libcurl for HTTP/HTTPS operations with NTLM authentication, including web browsers, automated scripts, and enterprise applications.
Mitigation strategies for CVE-2017-8816 primarily involve upgrading to curl and libcurl versions 7.57.0 or later, which contain patches addressing the integer overflow and buffer overflow conditions. Organizations should prioritize updating their systems and applications that depend on these libraries to prevent exploitation. Additionally, implementing input validation measures at the application level can provide defense-in-depth protection, limiting the length of user and password fields before they reach the curl library functions. Network-level controls such as rate limiting and monitoring for unusual authentication requests may help detect potential exploitation attempts. The ATT&CK framework classification for this vulnerability would fall under T1190 - Exploit Public-Facing Application, as it represents an exploitation of a public-facing library component that applications use for network communication. Security teams should also consider implementing memory protection mechanisms such as stack canaries, address space layout randomization, and data execution prevention to reduce the potential impact of any exploitation attempts. Regular vulnerability scanning and dependency management practices should include monitoring for outdated curl and libcurl installations to prevent similar issues from affecting operational environments.