Vulnerability · Published Mar 20, 2026 · Assigned by glibc

CVE-2026-4437gethostbyaddr and gethostbyaddr_r may incorrectly handle DNS response

High 7.5

In plain English

A high-severity out-of-bounds read in glibc from The GNU C Library. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 28% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.5High
Exploit odds (30 days)0.3%top 71.8% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
AlmaLinux:10glibc2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-all-langpacks2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-all-langpacks2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-benchtests2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-benchtests2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-common2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-common2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-devel2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-devel2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-doc2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-doc2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-gconv-extra2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-gconv-extra2.34-270.el9_8ALSA-2026:20597
AlmaLinux:9glibc-headers2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-aa2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-aa2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-af2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-af2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-agr2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-agr2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-ak2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-ak2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-am2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-am2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-an2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-an2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-anp2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-anp2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-ar2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-ar2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-as2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-as2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-ast2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-ast2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-ayc2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-ayc2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-az2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-az2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-be2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-be2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-bem2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-bem2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-ber2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-ber2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-bg2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-bg2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-bhb2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-bhb2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-bho2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-bho2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-bi2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-bi2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-bn2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-bn2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-bo2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-bo2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-br2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-br2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-brx2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-brx2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-bs2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-bs2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-byn2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-byn2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-ca2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-ca2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-ce2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-ce2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-chr2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-chr2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-ckb2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-ckb2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-cmn2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-cmn2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-crh2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-crh2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-cs2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-cs2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-csb2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-csb2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-cv2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-cv2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-cy2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-cy2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-da2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-da2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-de2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-de2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-doi2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-doi2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-dsb2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-dsb2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-dv2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-dv2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-dz2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-dz2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-el2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-el2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-en2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-en2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-eo2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-eo2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-es2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-es2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-et2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-et2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-eu2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-eu2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-fa2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-fa2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-ff2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-ff2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-fi2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-fi2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-fil2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-fil2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-fo2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-fo2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-fr2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-fr2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-fur2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-fur2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-fy2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-fy2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-ga2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-ga2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-gbm2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:10glibc-langpack-gd2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-gd2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-gez2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-gez2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-gl2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-gl2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-gu2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-gu2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-gv2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-gv2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-ha2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-ha2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-hak2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-hak2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-he2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-he2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-hi2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-hi2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-hif2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-hif2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-hne2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-hne2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-hr2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-hr2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-hsb2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-hsb2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-ht2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-ht2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-hu2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-hu2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-hy2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-hy2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-ia2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-ia2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-id2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-id2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-ig2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-ig2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-ik2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-ik2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-is2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-is2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-it2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-it2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-iu2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-iu2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-ja2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-ja2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-ka2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-ka2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-kab2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-kab2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-kk2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-kk2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-kl2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-kl2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-km2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-km2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-kn2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-kn2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-ko2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-ko2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-kok2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-kok2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-ks2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-ks2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-ku2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-ku2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-kv2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:10glibc-langpack-kw2.39-121.el10_2.alma.1ALSA-2026:19061
AlmaLinux:9glibc-langpack-kw2.34-270.el9_8ALSA-2026:20597
AlmaLinux:10glibc-langpack-ky2.39-121.el10_2.alma.1ALSA-2026:19061

Affected products (as reported)

VendorProductVersions
The GNU C Library glibc 2.34 – through 2.43

Weakness: CWE-125 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References