Mitigating PHP2Shell: Everything You Need to Know
Easily map the attack path and prioritize which CVEs are a threat to your organization
Miggo AIGenerate vendor-ready rules for the observed attack patterns, plus reasoning and safe deployment guidance
Miggo AIRoot Cause AnalysisThe vulnerability exists in the _IO_new_file_fopen function in libio/fileops.c, which is part of the glibc library and is called by the public fopen function. The analysis of the provided patch commit 129d706d77587e4d6627cc1ebef9be0f7cbc65f0 reveals that the parsing of the ,ccs= option in the mode string was flawed. The original code located the ,ccs= substring but did not properly handle cases where the character set name was empty. This would cause the __wcsmbs_named_conv function to read beyond the bounds of the mode string, resulting in a heap-based buffer overflow. The patch corrects this by explicitly calculating the length of the character set name, allocating a correctly sized buffer, and ensuring it is null-terminated before being used. Therefore, _IO_new_file_fopen is the direct vulnerable function where the flawed logic resides.
_IO_new_file_fopenlibio/fileops.c