CVE-2023-46852 in Memcached
Summary
by MITRE • 10/27/2023
In Memcached before 1.6.22, a buffer overflow exists when processing multiget requests in proxy mode, if there are many spaces after the "get" substring.
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Analysis
by VulDB Data Team • 02/17/2026
The vulnerability CVE-2023-46852 represents a critical buffer overflow flaw in Memcached versions prior to 1.6.22 that specifically affects the proxy mode functionality when processing multiget requests. This issue arises from inadequate input validation and memory management during the parsing of client requests, creating a pathway for malicious actors to exploit the system through carefully crafted malformed requests. The vulnerability is particularly concerning because Memcached serves as a widely deployed distributed memory caching system that many applications rely upon for performance optimization, making it a prime target for attackers seeking to disrupt services or potentially execute arbitrary code.
The technical root cause of this vulnerability lies in how Memcached handles multiget requests when operating in proxy mode, where the software acts as an intermediary between client applications and backend memcached servers. When processing these requests, the system fails to properly validate the number of spaces following the "get" command substring, allowing an attacker to craft requests with excessive whitespace that exceeds the allocated buffer boundaries. This buffer overflow condition occurs because the parsing logic does not enforce proper bounds checking on the input data, particularly when multiple spaces are present after the command identifier. The flaw manifests as a classic stack-based buffer overflow where the excessive whitespace causes memory corruption that can be leveraged to overwrite adjacent memory locations, potentially leading to denial of service or arbitrary code execution depending on the system configuration and memory layout.
The operational impact of this vulnerability extends beyond simple service disruption, as it can be exploited to cause widespread availability issues across systems that depend on Memcached for caching operations. Attackers can leverage this vulnerability to perform denial of service attacks against memcached instances, causing them to crash or become unresponsive, which subsequently affects all applications relying on those caching services. The vulnerability is particularly dangerous in environments where Memcached operates in proxy mode, as this configuration is commonly used in high-traffic web applications and microservices architectures where caching performance is critical. The exploitability of this issue is enhanced by the fact that it requires minimal complexity to craft malicious requests, making it an attractive target for automated attack tools and script kiddies seeking to disrupt services.
Mitigation strategies for CVE-2023-46852 primarily focus on upgrading to Memcached version 1.6.22 or later, which includes proper bounds checking and input validation mechanisms that prevent the buffer overflow condition. Organizations should also implement network-level protections such as firewall rules that restrict access to Memcached ports to trusted sources only, and consider deploying intrusion detection systems that can identify anomalous request patterns indicative of exploitation attempts. Additionally, administrators should regularly audit their Memcached configurations to ensure that proxy mode is only enabled when absolutely necessary, and implement proper monitoring and logging of all memcached activities to detect potential exploitation attempts. The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and represents a typical example of how insufficient input validation can lead to critical security flaws in caching systems that form the backbone of modern web applications. Organizations should also consider implementing application-level protections such as request rate limiting and input sanitization to further reduce the attack surface and provide defense-in-depth measures against similar vulnerabilities that may exist in other components of their infrastructure.