Squid before 2.3STABLE5 in HTTP accelerator mode does not enable access control lists (ACLs) when the httpd_accel_host and http_accel_with_proxy off settings are used, which allows attackers to bypass the ACLs and conduct unauthorized activities such as port scanning.

When using the LD_PRELOAD environmental variable in SUID or SGID applications, glibc does not verify that preloaded libraries in /etc/ld.so.cache are also SUID/SGID, which could allow a local user to overwrite arbitrary files by loading a library from /lib or /usr/lib.

sdiff 2.7 in the diffutils package allows local users to overwrite files via a symlink attack.

squid 2.3 and earlier allows local users to overwrite arbitrary files via a symlink attack in some configurations.