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CVE-2021-20294 is a stack buffer overflow vulnerability in the readelf utility of binutils version 2.35. The vulnerability occurs when readelf processes a specially crafted file, allowing an attacker to trigger an out-of-bounds write of arbitrary data to the stack. This is due to insufficient bounds checking when handling input data within readelf.
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1 valid exploit after Mallory filtered fakes, detection scripts, and README-only repos.
This repository provides a proof-of-concept (POC) exploit for CVE-2021-20294, a vulnerability in GNU binutils' readelf utility (version 2.35). The exploit consists of a C source file (poc.c) that defines a function with an excessively long symbol version string using inline assembly. A version script (poc.ver) is also provided to control symbol visibility. The README details compilation steps to produce a shared object (poc.so) and instructions to run readelf against it, which triggers the vulnerability. The details.md file provides background and references to the vulnerability. The exploit demonstrates the issue by causing readelf to process a malformed ELF file, potentially leading to a crash or other unintended behavior. The attack vector is local, requiring the attacker to supply a crafted ELF file to a vulnerable readelf instance. No network endpoints are involved. The repository is structured with clear separation between documentation, exploit code, and build instructions.
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