CVE-2026-4437— gethostbyaddr and gethostbyaddr_r may incorrectly handle DNS response
Quick assessment
Affected
The GNU C Library glibc
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.
GNU C Library是GNU社区的一种按照LGPL许可协议发布的开源免费的C语言编译程序。 GNU C Library 2.34至2.43版本存在安全漏洞，该漏洞源于gethostbyaddr或gethostbyaddr_r函数可能将DNS响应的非答案部分视为有效答案，违反DNS规范。
Possible ATT&CK Techniques 1 AI
T1568.002 · Domain Generation AlgorithmsAffected Version Matrix 1
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| The GNU C Library | glibc | 2.34≤ 2.43 |
affected |
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I. Basic Information for CVE-2026-4437
Vulnerability Information
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Vulnerability Title
gethostbyaddr and gethostbyaddr_r may incorrectly handle DNS response
Source: CVE Program / CVE List V5
Vulnerability Description
Calling gethostbyaddr or gethostbyaddr_r with a configured nsswitch.conf that specifies the library's DNS backend in the GNU C Library version 2.34 to version 2.43 could, with a crafted response from the configured DNS server, result in a violation of the DNS specification that causes the application to treat a non-answer section of the DNS response as a valid answer.
Source: CVE Program / CVE List V5
CVSS Information
N/A
Source: CVE Program / CVE List V5
Vulnerability Type
跨界内存读
Source: CVE Program / CVE List V5
Vulnerability Title
GNU C Library 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
GNU C Library是GNU社区的一种按照LGPL许可协议发布的开源免费的C语言编译程序。 GNU C Library 2.34至2.43版本存在安全漏洞，该漏洞源于gethostbyaddr或gethostbyaddr_r函数可能将DNS响应的非答案部分视为有效答案，违反DNS规范。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)
Affected Products
| Vendor | Product | Affected Versions | CPE | Subscribe |
|---|---|---|---|---|
| The GNU C Library | glibc | 2.34 ~ 2.43 | - |
|
II. Public POCs for CVE-2026-4437
| # | POC Description | Source Link | Shenlong Link |
|---|
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Other References for CVE-2026-4437 (1)
IV. Related Vulnerabilities
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V. Comments for CVE-2026-4437
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