CVE-2021-43618 in Multiple Precision Arithmetic Library
Summary
by MITRE • 11/15/2021
GNU Multiple Precision Arithmetic Library (GMP) through 6.2.1 has an mpz/inp_raw.c integer overflow and resultant buffer overflow via crafted input, leading to a segmentation fault on 32-bit platforms.
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Analysis
by VulDB Data Team • 10/17/2025
The GNU Multiple Precision Arithmetic Library GMP version 6.2.1 contains a critical integer overflow vulnerability in the mpz/inp_raw.c component that specifically affects 32-bit platforms. This vulnerability arises from improper handling of input data during the parsing of raw integer values, creating conditions where maliciously crafted input can trigger arithmetic overflow calculations. The flaw manifests when the library attempts to process input data that exceeds the maximum representable value for 32-bit signed integers, causing the overflow to wrap around and result in unexpected memory access patterns. The vulnerability is particularly concerning because it leads to buffer overflow conditions that can cause segmentation faults and potentially enable arbitrary code execution in vulnerable applications. The integer overflow occurs during the calculation of buffer sizes needed to store parsed input data, where the computation does not properly validate that the resulting value will fit within the allocated memory boundaries. This type of vulnerability falls under the CWE-190 category of Integer Overflow or Wraparound, which represents a fundamental flaw in arithmetic operations that can lead to memory corruption and system instability.
The operational impact of CVE-2021-43618 extends beyond simple segmentation faults to potentially compromise entire systems that rely on GMP for cryptographic operations, mathematical computations, or data processing tasks. Applications using GMP for parsing user input, handling serialized data, or processing external files become vulnerable to this attack vector when deployed on 32-bit architectures. The vulnerability is particularly dangerous in environments where applications process untrusted input from network sources, file uploads, or user-generated content, as attackers can craft specific input sequences to trigger the overflow condition. On 32-bit platforms, the limited address space and smaller integer types make the overflow conditions more likely to result in exploitable memory corruption patterns. This vulnerability aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter and T1203 for Exploitation for Client Execution, as it represents a foundational weakness that can be leveraged to execute arbitrary code through memory corruption attacks.
Mitigation strategies for CVE-2021-43618 should focus on immediate patching of GMP to version 6.2.2 or later, which contains the necessary fixes for the integer overflow conditions. System administrators should prioritize updating all affected systems and applications that depend on GMP, particularly those running on 32-bit platforms where the vulnerability is most pronounced. Additionally, implementing input validation measures can help reduce the attack surface by sanitizing or rejecting malformed input data before it reaches the vulnerable GMP parsing functions. Organizations should also consider deploying runtime protections such as address space layout randomization ASLR, stack canaries, and non-executable stack protections to make exploitation more difficult even if the vulnerability is present. Regular security audits and penetration testing should include verification that applications are not vulnerable to similar integer overflow conditions in other libraries or components. The fix implemented by the GMP maintainers specifically addresses the integer overflow in the mpz_inp_raw function by adding proper bounds checking and validation of input parameters before performing arithmetic operations that could lead to buffer overflows. This remediation approach follows established security practices for preventing integer overflow vulnerabilities as outlined in the CERT Secure Coding Standards and aligns with defensive programming principles that emphasize input validation and proper error handling in arithmetic operations.