CVE-2026-4438
DNS Spoofing via gethostbyaddr in GNU C Library
Publication date: 2026-03-20
Last updated on: 2026-04-07
Assigner: GNU C Library
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| gnu | glibc | From 2.34 (inc) to 2.43 (inc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-88 | The product constructs a string for a command to be executed by a separate component in another control sphere, but it does not properly delimit the intended arguments, options, or switches within that command string. |
| CWE-20 | The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability occurs when the functions gethostbyaddr or gethostbyaddr_r are called in the GNU C library versions 2.34 to 2.43 with a configured nsswitch.conf that specifies the library's DNS backend. Under these conditions, the functions could return an invalid DNS hostname to the caller, which violates the DNS specification.
How can this vulnerability impact me? :
The impact of this vulnerability is that applications relying on gethostbyaddr or gethostbyaddr_r for hostname resolution may receive invalid DNS hostnames. This could lead to incorrect hostname information being used in network communications or logging, potentially causing failures, misrouting, or security issues related to hostname validation.
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
I don't know
How can this vulnerability be detected on my network or system? Can you suggest some commands?
I don't know
What immediate steps should I take to mitigate this vulnerability?
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