A security vulnerability has been discovered in the c-ares library that is bundled with all versions of Node.js. Due to the difficulty of triggering and making use of this vulnerability we currently consider this a low-severity security flaw for Node.js users.

More information at https://c-ares.haxx.se/adv20160929.html

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.

0-byte UDP payload DoS in c-ares

The c-ares function aresparsenaptrreply(), which is used for parsing NAPTR responses, could be triggered to read memory outside of the given input buffer if the passed in DNS response packet was crafted in a particular way.

A Node.js application that allows an attacker to trigger a DNS request for a host of their choice could trigger a Denial of service by getting the application to resolve a DNS record with a larger number of responses.

Versions 12.16.3 and higher on the 12.x release line

Versions 14.13.0 and higher on the 14.x release line

All versions of the 15.x release line

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.

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.

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)

A flaw was found in c-ares library, where a missing input validation check of host names returned by DNS (Domain Name Servers) can lead to output of wrong hostnames which might potentially lead to Domain Hijacking. The highest threat from this vulnerability is to confidentiality and integrity as well as system availability.