0-byte UDP payload DoS in c-ares

aresinetnetpton() is vulnerable to a buffer underflow for certain ipv6 addresses, in particular "0::00:00:00/2" was found to cause an issue. C-ares only uses this function internally for configuration purposes which would require an administrator to configure such an address via aressetsortlist().

CVE-2023-31130. Moderate. Buffer Underwrite in aresinetnetpton() (https://github.com/c-ares/c-ares/security/advisories/GHSA-x6mf-cxr9-8q6v)

c-ares is an asynchronous resolver library. When /dev/urandom or RtlGenRandom() are unavailable, c-ares uses rand() to generate random numbers used for DNS query ids. This is not a CSPRNG, and it is also not seeded by srand() so will generate predictable output. Input from the random number generator is fed into a non-compilant RC4 implementation and may not be as strong as the original RC4 implementation. No attempt is made to look for modern OS-provided CSPRNGs like arc4random() that is widely available. This issue has been fixed in version 1.19.1.

A flaw was found in the c-ares package. The aressetsortlist is missing checks about the validity of the input string which allows a possible arbitrary length stack overflow. This issue may cause a denial of service or a limited impact on confidentiality and integrity.

c-ares is an asynchronous resolver library. When cross-compiling c-ares and using the autotools build system, CARESRANDOMFILE will not be set, as seen when cross compiling aarch64 android. This will downgrade to using rand() as a fallback which could allow an attacker to take advantage of the lack of entropy by not using a CSPRNG. This issue was patched in version 1.19.1.