---
id: CVE-2026-6238
title: Buffer overread in ns_printrrf with corrupted RDATA field
summary: >-
  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 r…
severity: medium
cvss: 6.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L'
cvssSource: adp
cwe:
  - CWE-126
vendor: The GNU C Library
product: glibc
affected:
  - glibc >= 2.0.1 <= 2.43
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-04-28T18:51:21.285963Z'
published: '2026-04-28'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T01:12:16.267Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-6238'
references:
  - url: 'https://sourceware.org/bugzilla/show_bug.cgi?id=34069'
  - url: >-
      https://inbox.sourceware.org/libc-announce/7a655d55-276f-41fe-b550-feb3ebb2ce91@redhat.com/T/#u
tags:
  - cve.org
epss: 0.00444
epssPercentile: 0.36973
ingestedAt: '2026-10-15T05:52:46.048Z'
---

## Overview

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.

## Affected

- `glibc >= 2.0.1 <= 2.43`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.