GNU Bash vulnerabilities

Off-by-one error in the read_token_word function in parse.y in GNU Bash through 4.3 bash43-026 allows remote attackers to cause a denial of service (out-of-bounds array access and application crash) or possibly have unspecified other impact via deeply nested for loops.

The redirection implementation in parse.y in GNU Bash through 4.3 bash43-026 allows remote attackers to cause a denial of service (out-of-bounds array access and application crash) or possibly have unspecified other impact via crafted use of here documents.

GNU Bash through 4.3 bash43-026 does not properly parse function definitions in the values of environment variables, allowing remote attackers to execute arbitrary code or cause a denial of service via a crafted environment.

An issue was discovered in disable_priv_mode in shell.c in GNU Bash through 5.0 patch 11. By default, if Bash is run with its effective UID not equal to its real UID, it will drop privileges by setting its effective UID to its real UID. However, it does so incorrectly. On Linux and other systems that support "saved UID" functionality, the saved UID is not dropped. An attacker with command execution in the shell can use "enable -f" for runtime loading of a new builtin, which can be a shared object that calls setuid() and therefore regains privileges.