Net::DNS::DomainName::decode follows RFC 1035 compression pointers by recursing into itself with no depth limit. An attacker can craft a DNS response containing a long chain of two‑byte pointers that reference earlier positions, creating a recursion depth of thousands of frames. This depth can exceed the Perl interpreter’s C stack, causing a segmentation fault and stopping the application that parsed the DNS packet. The result is a denial of service to any service or daemon that relies on Net::DNS to decode untrusted DNS data.

The affected product is NLNETLABS:Net::DNS, a Perl module used for DNS processing. All releases through version 1.55 are vulnerable, regardless of the operating system or configuration. Any Perl script, service, or application that imports Net::DNS 1.55 or earlier for decoding DNS responses from the network is impacted.

An adversary only needs to send a malicious DNS packet to the vulnerable endpoint. The packet can contain a deep compression pointer chain that saturates the call stack, causing the interpreter to crash. The impact is a denial of service to any application that uses Net::DNS to parse untrusted DNS data. The vulnerability can be exploited over a network with no special permissions, making it straightforward. However, the EPSS score of less than 1% indicates that, in practice, the probability of exploitation is low, and the vulnerability is not currently documented in CISA KEV. Despite this, the CVSS of 7.5 and the potential for a complete service interruption warrant prompt patching.