CVE-2026-4438

🔶 medium

Summary

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 result in an invalid DNS hostname being returned to the caller in violation of the DNS specification.

CVSS Score

5.4

Medium

EPSS Score

0.1

Exploit Probability

Published Date

2026-03-20

First Seen: 2026-03-21

📊 Relative Risk Intelligence

This CVE is Lower Risk - more severe than 22.8% of all 329,456 vulnerabilities in our database.

#254,389

Below average severity

Severity Percentile

🎯 CISA SSVC Assessment Updated: Mar 23, 2026

🔍 Exploitation Status

None

No known exploits

⚙️ Automatable

Requires human interaction

💥 Technical Impact

Partial

Limited system impact

🏆 Discovered By

Antonio Maini (0rbitingZer0) - 0rbitingZer0@proton.me

SSVC data provided by CISA

Last Modified 2026-04-07

Source NVD 🔗

CVSS Vector 3.1 CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

CWE IDs (Weakness Types)

CWE-20 CWE-88

📦 Affected Products 1

Vendor	Product	Status	Affected Versions
gnu	glibc	Affected	> 2.34 < 2.43

🔗 References 1

https://sourceware.org/bugzilla/show_bug.cgi?id=34015

Exploit Issue Tracking Patch

🔗 Related CVEs 6

CVE ID	Severity	CVSS	EPSS	Summary	Published
CVE-2026-6238	🔶 medium	6.5	0.3	The deprecated functions ns_printrrf, ns_printrr and fp_nquery in the GNU C Library version 2.0.1 to version 2.43 fail t...	2026-04-28
CVE-2026-5435	⚠️ high	7.3	0.1	The deprecated functions ns_printrrf, ns_printrr and fp_nquery in the GNU C Library version 2.2 and newer fail to enforc...	2026-04-28
CVE-2026-4046	⚠️ high	7.5	0.0	The iconv() function in the GNU C Library versions 2.43 and earlier may crash due to an assertion failure when convertin...	2026-03-30
CVE-2026-4437	⚠️ high	7.5	0.1	Calling gethostbyaddr or gethostbyaddr_r with a configured nsswitch.conf that specifies the library's DNS backend in the...	2026-03-20
CVE-2026-3904	🔶 medium	6.2	0.0	Calling NSS-backed functions that support caching via nscd may call the nscd client side code and in the GNU C Library ...	2026-03-11
CVE-2025-15281	⚠️ high	7.5	0.1	Calling wordexp with WRDE_REUSE in conjunction with WRDE_APPEND in the GNU C Library version 2.0 to version 2.42 may cau...	2026-01-20

These CVEs affect the same products