CVE-2019-14873 in libc Library
Summary
by MITRE
In the __multadd function of the newlib libc library, prior to versions 3.3.0 (see newlib/libc/stdlib/mprec.c), Balloc is used to allocate a big integer, however no check is performed to verify if the allocation succeeded or not. This will trigger a null pointer dereference bug in case of a memory allocation failure.
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Analysis
by VulDB Data Team • 08/27/2025
The vulnerability described in CVE-2019-14873 represents a critical memory safety issue within the newlib libc library, specifically affecting the __multadd function in versions prior to 3.3.0. This flaw exists in the file newlib/libc/stdlib/mprec.c where the Balloc function is employed to allocate memory for big integer operations. The issue stems from the absence of error checking mechanisms that should validate whether memory allocation requests succeed or fail, creating a scenario where the program continues execution despite allocation failures.
The technical implementation of this vulnerability involves the improper handling of memory allocation failures within the mathematical operations library component. When Balloc attempts to allocate memory for large integer computations and encounters a failure, it returns a null pointer without any validation checks in the calling function. This oversight allows the program to proceed with a null pointer reference in subsequent operations, ultimately resulting in a null pointer dereference exception that can cause program termination or potentially enable exploitation.
The operational impact of this vulnerability extends beyond simple program crashes, as it represents a classic null pointer dereference flaw that can be exploited by malicious actors to gain unauthorized access or cause denial of service conditions. This type of vulnerability falls under CWE-476 which specifically addresses null pointer dereference conditions in software implementations. The flaw particularly affects systems relying on newlib's mathematical computation capabilities where large integer operations are performed, potentially impacting embedded systems, network infrastructure, and any application stack utilizing this library component.
From an adversarial perspective, this vulnerability aligns with ATT&CK technique T1059.007 for command and script injection, as exploitation could allow attackers to manipulate program execution flow through memory corruption. The vulnerability demonstrates poor defensive programming practices where error handling is insufficient to prevent execution of invalid memory references. Organizations utilizing embedded systems, IoT devices, or any software stack that depends on newlib libc for mathematical operations should prioritize immediate patching of affected versions, as the vulnerability can be triggered through normal program execution paths involving large integer arithmetic operations.
The fix for this vulnerability required implementing proper error checking after memory allocation calls within the Balloc function usage, ensuring that null pointer return values are handled gracefully rather than allowing the program to continue execution with invalid memory references. This remediation approach aligns with secure coding practices that emphasize defensive programming and proper resource management. The vulnerability serves as a reminder of the critical importance of memory allocation validation in mathematical libraries and the potential for seemingly minor oversight to create significant security implications in system reliability and safety.