neon before 0.28.6, when expat is used, does not properly detect recursion during entity expansion, which allows context-dependent attackers to cause a denial of service (memory and CPU consumption) via a crafted XML document containing a large number of nested entity references, a similar issue to CVE-2003-1564.

neon before 0.28.6, when OpenSSL or GnuTLS is used, does not properly handle a '\0' character in a domain name in the subject's Common Name (CN) field of an X.509 certificate, which allows man-in-the-middle attackers to spoof arbitrary SSL servers via a crafted certificate issued by a legitimate Certification Authority, a related issue to CVE-2009-2408.

neon 0.28.0 through 0.28.2 allows remote servers to cause a denial of service (NULL pointer dereference and crash) via vectors related to Digest authentication, Digest domain parameter support, and the parsedomain function.