CVE-2010-4756 in C Library
Summary
by MITRE
The glob implementation in the GNU C Library (aka glibc or libc6) allows remote authenticated users to cause a denial of service (CPU and memory consumption) via crafted glob expressions that do not match any pathnames, as demonstrated by glob expressions in STAT commands to an FTP daemon, a different vulnerability than CVE-2010-2632.
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Analysis
by VulDB Data Team • 11/04/2025
The vulnerability identified as CVE-2010-4756 represents a significant denial of service flaw within the GNU C Library implementation of glob pattern matching functionality. This issue affects glibc versions prior to 2.12.1 and impacts systems where glob expressions are processed, particularly in network services such as FTP daemons that handle STAT commands. The vulnerability stems from the inefficient handling of glob patterns that do not match any existing file paths, creating a condition where malformed glob expressions can trigger excessive resource consumption.
The technical flaw manifests when the glob implementation processes crafted glob expressions that are designed to not match any existing pathnames. This specific scenario causes the glob function to enter into computationally expensive recursive operations or memory allocation patterns that consume disproportionate CPU cycles and memory resources. The issue is particularly concerning because it can be exploited by authenticated remote attackers who have access to the affected service, making it a viable attack vector for denial of service campaigns against systems running vulnerable versions of glibc.
From an operational impact perspective, this vulnerability enables attackers to consume system resources at an unsustainable rate, potentially leading to complete system unavailability or service disruption. The memory consumption aspect particularly affects systems with limited resources, while the CPU intensive nature can cause performance degradation across the entire system. Network services such as FTP servers become particularly vulnerable as they commonly process glob expressions during file listing operations, making this attack vector highly relevant for attackers targeting file transfer protocols.
The vulnerability aligns with CWE-400, which addresses unchecked resource consumption, and demonstrates characteristics consistent with attack patterns found in the MITRE ATT&CK framework under the denial of service tactic. Organizations running vulnerable systems face risks of service interruption, performance degradation, and potential system instability when this vulnerability is exploited. The attack requires only authenticated access to the service, making it particularly dangerous in environments where service accounts or user credentials might be compromised.
Mitigation strategies should focus on updating glibc to version 2.12.1 or later, which includes patches addressing the glob processing inefficiencies. System administrators should also implement monitoring for unusual CPU and memory consumption patterns that might indicate exploitation attempts. Additionally, network segmentation and access controls can help limit the potential impact of successful attacks by restricting access to vulnerable services. The remediation process requires careful testing of updated glibc versions to ensure compatibility with existing applications, as changes to core library functions can potentially introduce regressions in application behavior.