CVE-2020-29367 in C-Blosc2
Summary
by MITRE • 11/27/2020
blosc2.c in Blosc C-Blosc2 through 2.0.0.beta.5 has a heap-based buffer overflow when there is a lack of space to write compressed data.
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Analysis
by VulDB Data Team • 04/25/2025
The vulnerability identified as CVE-2020-29367 resides within the blosc2.c component of the C-Blosc2 compression library version 2.0.0.beta.5 and earlier. This heap-based buffer overflow represents a critical security flaw that can be exploited to compromise system integrity and potentially execute arbitrary code. The vulnerability manifests when the compression process encounters insufficient space to accommodate the compressed output data, creating a scenario where memory boundaries are violated.
The technical implementation of this flaw occurs within the compression algorithm's memory management routines where insufficient bounds checking allows data to be written beyond allocated heap buffers. This particular vulnerability falls under the CWE-121 heap-based buffer overflow category, which is classified as a serious memory safety issue that can lead to denial of service, information disclosure, or remote code execution depending on the exploitation context. The flaw demonstrates poor input validation and inadequate buffer size calculations during the compression process where the system fails to properly verify that the destination buffer can accommodate the expected compressed output.
From an operational perspective, this vulnerability poses significant risks to systems that rely on C-Blosc2 for data compression, particularly in environments where untrusted input data is processed. Attackers could leverage this flaw by crafting malicious input data that triggers the buffer overflow condition, potentially leading to system crashes or unauthorized code execution. The impact extends beyond simple denial of service as the heap corruption can be exploited to manipulate program execution flow, making it a particularly dangerous vulnerability in security-sensitive applications. The vulnerability affects systems where C-Blosc2 is integrated into larger software ecosystems, including data processing pipelines, scientific computing frameworks, and storage systems that utilize compression.
Mitigation strategies should prioritize immediate patching of affected systems to the latest stable release of C-Blosc2 that addresses this buffer overflow issue. Organizations should implement comprehensive input validation measures and consider deploying runtime protections such as address space layout randomization and stack canaries to reduce exploitability. The ATT&CK framework categorizes this vulnerability under the T1070 technique for indicator removal and potentially T1203 for legitimate program exploitation, making it a target for both defensive and offensive cybersecurity operations. System administrators should monitor for unusual memory access patterns and implement network segmentation to limit the potential blast radius of successful exploitation attempts. Additionally, regular security assessments and penetration testing should be conducted to identify similar memory safety issues within the broader software ecosystem that may be susceptible to similar vulnerabilities.