The deprecated functions ns_printrrf, ns_printrr and fp_nquery in the GNU C Library version 2.2 and newer fail to validate the RDATA content against the RDATA length in a DNS response when processing LOC, CERT, TKEY or TSIG records, which may allow an attacker to craft a DNS response, causing a target application to crash or read uninitialized memory.

These functions are for application debugging only and hence not in the path of code executed by the DNS resolver.  Further, they have been deprecated since version 2.34 and should not be used by any new applications.  Applications should consider porting away from these interfaces since they may be removed in future versions.

The deprecated functions ns_printrrf, ns_printrr and fp_nquery in the GNU C Library version 2.0.1 to version 2.43 fail to validate the RDATA content against the RDATA length in a DNS response when processing A6, CERT, LOC, TKEY or TSIG records, which may allow an attacker to craft a DNS response, causing a target application to crash or read uninitialized memory.

These functions are for application debugging only and hence not in the path of code executed by the DNS resolver.  Further, they have been deprecated since version 2.34 and should not be used by any new applications.  Applications should consider porting away from these interfaces since they may be removed in future versions.

[{"vendor":"The GNU C Library","product":"glibc","defaultStatus":"affected","versions":[{"version":"2.2","lessThanOrEqual":"0","versionType":"custom","status":"affected"}]}]

[{"vendor":"The GNU C Library","product":"glibc","defaultStatus":"affected","versions":[{"version":"2.0.1","lessThanOrEqual":"2.43","versionType":"custom","status":"affected"}]}]

{"timestamp":"2026-04-28T18:51:21.285963Z","id":"CVE-2026-6238","options":[{"exploitation":"none"},{"automatable":"yes"},{"technicalImpact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}

[{"vendor":"The GNU C Library","product":"glibc","defaultStatus":"affected","versions":[{"version":"2.2","lessThanOrEqual":"0","versionType":"custom","status":"affected"}]}]

OR
          *cpe:2.3:a:gnu:glibc:*:*:*:*:*:*:*:* versions from (including) 2.2 

GNU C Library: https://inbox.sourceware.org/libc-announce/[email protected]/T/#u Types: Third Party Advisory

GNU C Library: https://sourceware.org/bugzilla/show_bug.cgi?id=34069 Types: Issue Tracking

AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L

The deprecated functions ns_printrrf, ns_printrr and fp_nquery in the GNU C Library version 2.2 and newer fail to validate the RDATA content against the RDATA length in a DNS response when processing LOC, CERT, TKEY or TSIG records, which may allow an attacker to craft a DNS response, causing a target application to crash or read uninitialized memory.

These functions are for application debugging only and hence not in the path of code executed by the DNS resolver.  Further, they have been deprecated since version 2.34 and should not be used by any new applications.  Applications should consider porting away from these interfaces since they may be removed in future versions.

CWE-126

https://inbox.sourceware.org/libc-announce/[email protected]/T/#u

https://sourceware.org/bugzilla/show_bug.cgi?id=34069