In the Linux kernel, the following vulnerability has been resolved: SUNRPC: svcauthgss: avoid NULL deref on zero length gsstoken in gssreadproxyverf A zero length gsstoken results in pages == 0 and intoken->pages[0] is NULL. The code unconditionally evaluates pageaddress(in_token->pages[0]) for the initial memcpy, which can dereference NULL even when the copy length is 0. Guard the first memcpy so it only runs when length > 0.