In Vinyl Cache before 9.0,2, workspace buffer overflow vulnerability was found in the .upper() and .lower() string type methods of VCL. This can be used as a remote denial of service (DoS) vector to make the child process segfault or assert, and then restart. Effectively exploiting this vulnerability requires prior knowledge about the VCL in use and the ability to craft a request that contains a string that is long enough to fill the remaining workspace at the call site while staying under the different request size limits (http_req_size, http_req_hdr_len, etc.).
Use of .upper() or .lower() string type methods in VCL
replace the .upper() and
.lower() VCL type method calls by their respective vmod_std counterparts:
std.toupper() and std.tolower().
Update to unaffected Version