CVE-2026-89092

/// Technical description

The nscd service in the GNU C Library 2.3.4 onwards may crash due to a

stack overflow when a malicious DNS server returns too large a response

for a DNS query, resulting in degraded DNS resolution for the system.

Exploitation of this bug needs a system that has nscd enabled and using

an untrusted DNS server for name resolution, with the compromised DNS

server being capable of processing records large enough to result in a

stack overflow in an nscd thread stack.  During experimentation, bind 9

was unable to handle large records, but that could change in future or

with a different name server.  In typical installations, nscd is

executed in an isolated context as its own user without a shell, due to

which any compromise of that service is isolated.

There is a remote possibility of nscd cache corruption if an attacker

manages to get the stack pointer into a desired point in the heap,

potentially resulting in other caches in nscd being overwritten with

corrupt data through

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References