CVE-2026-6238: CWE-126 Buffer over-read in The GNU C Library glibc
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.
AI Analysis
Technical Summary
The vulnerability in glibc involves the deprecated debugging functions ns_printrrf, ns_printrr, and fp_nquery, which do not validate RDATA content length against the RDATA length in DNS responses when processing A6, CERT, LOC, TKEY, or TSIG records. This can lead to buffer over-read conditions, causing application crashes or exposure of uninitialized memory. Since these functions are intended only for debugging and have been deprecated since version 2.34, they are not part of the DNS resolver execution path. The affected versions include 2.0.1 through 2.43. No official remediation or patch is currently documented.
Potential Impact
An attacker can craft malicious DNS responses that exploit the buffer over-read in the deprecated debugging functions, potentially causing the target application to crash or read uninitialized memory. However, since these functions are deprecated and not used in the DNS resolver code path, the practical impact is limited to applications that explicitly use these debugging interfaces.
Mitigation Recommendations
No official patch or remediation level is currently documented. Since the vulnerable functions are deprecated since version 2.34 and may be removed in future releases, applications should avoid using ns_printrrf, ns_printrr, and fp_nquery and migrate away from these interfaces. Monitoring for updates from the GNU C Library project is recommended to obtain any future fixes.
CVE-2026-6238: CWE-126 Buffer over-read in The GNU C Library glibc
Description
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.
CVSS v3.1
Score 6.5medium
Affected software
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability in glibc involves the deprecated debugging functions ns_printrrf, ns_printrr, and fp_nquery, which do not validate RDATA content length against the RDATA length in DNS responses when processing A6, CERT, LOC, TKEY, or TSIG records. This can lead to buffer over-read conditions, causing application crashes or exposure of uninitialized memory. Since these functions are intended only for debugging and have been deprecated since version 2.34, they are not part of the DNS resolver execution path. The affected versions include 2.0.1 through 2.43. No official remediation or patch is currently documented.
Potential Impact
An attacker can craft malicious DNS responses that exploit the buffer over-read in the deprecated debugging functions, potentially causing the target application to crash or read uninitialized memory. However, since these functions are deprecated and not used in the DNS resolver code path, the practical impact is limited to applications that explicitly use these debugging interfaces.
Mitigation Recommendations
No official patch or remediation level is currently documented. Since the vulnerable functions are deprecated since version 2.34 and may be removed in future releases, applications should avoid using ns_printrrf, ns_printrr, and fp_nquery and migrate away from these interfaces. Monitoring for updates from the GNU C Library project is recommended to obtain any future fixes.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- glibc
- Date Reserved
- 2026-04-13T16:56:08.986Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 69f1649ccbff5d861047ed13
Added to database: 04/29/2026, 01:53:32 UTC
Last enriched: 07/15/2026, 11:24:57 UTC
Last updated: 07/31/2026, 19:23:00 UTC
Views: 95
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