CVE-2026-6238
Buffer overread in ns_printrrf with corrupted RDATA field
Description
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.
INFO
Published Date :
April 28, 2026, 7:37 p.m.
Last Modified :
May 4, 2026, 5:57 p.m.
Remotely Exploit :
Yes !
Source :
3ff69d7a-14f2-4f67-a097-88dee7810d18
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | 134c704f-9b21-4f2e-91b3-4a467353bcc0 |
Solution
- Update GNU C Library to a recent version.
- Remove usage of ns_printrrf, ns_printrr, and fp_nquery.
- Port applications away from deprecated DNS functions.
Public PoC/Exploit Available at Github
CVE-2026-6238 has a 1 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-6238.
| URL | Resource |
|---|---|
| https://inbox.sourceware.org/libc-announce/[email protected]/T/#u | Third Party Advisory |
| https://sourceware.org/bugzilla/show_bug.cgi?id=34069 | Issue Tracking |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-6238 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-6238
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
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Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-6238 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-6238 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
May. 04, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:gnu:glibc:*:*:*:*:*:*:*:* versions from (including) 2.2 Added Reference Type GNU C Library: https://inbox.sourceware.org/libc-announce/[email protected]/T/#u Types: Third Party Advisory Added Reference Type GNU C Library: https://sourceware.org/bugzilla/show_bug.cgi?id=34069 Types: Issue Tracking -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Apr. 28, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L -
New CVE Received by 3ff69d7a-14f2-4f67-a097-88dee7810d18
Apr. 28, 2026
Action Type Old Value New Value Added Description 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. Added CWE CWE-126 Added Reference https://inbox.sourceware.org/libc-announce/[email protected]/T/#u Added Reference https://sourceware.org/bugzilla/show_bug.cgi?id=34069