OESA-2026-1803 (CVE-2026-4437)
Vulnerability from osv_openeuler – Published: 2026-04-03 11:10 – Updated: 2026-08-06 11:10 – Source websiteThe GNU C Library project provides the core libraries for the GNU system and GNU/Linux systems, as well as many other systems that use Linux as the kernel. These libraries provide critical APIs including ISO C11, POSIX.1-2008, BSD, OS-specific APIs and more. These APIs include such foundational facilities as open, read, write, malloc, printf, getaddrinfo, dlopen, pthread_create, crypt, login, exit and more.
Security Fix(es):
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.(CVE-2026-4437)
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.(CVE-2026-4438)
| URL | Type | |
|---|---|---|
{
"affected": [
{
"ecosystem_specific": {
"aarch64": [
"glibc-2.38-98.oe2403sp1.aarch64.rpm",
"glibc-all-langpacks-2.38-98.oe2403sp1.aarch64.rpm",
"glibc-common-2.38-98.oe2403sp1.aarch64.rpm",
"glibc-debuginfo-2.38-98.oe2403sp1.aarch64.rpm",
"glibc-debugsource-2.38-98.oe2403sp1.aarch64.rpm",
"glibc-debugutils-2.38-98.oe2403sp1.aarch64.rpm",
"glibc-devel-2.38-98.oe2403sp1.aarch64.rpm",
"glibc-locale-archive-2.38-98.oe2403sp1.aarch64.rpm",
"glibc-locale-source-2.38-98.oe2403sp1.aarch64.rpm",
"glibc-nss-devel-2.38-98.oe2403sp1.aarch64.rpm",
"libnsl-2.38-98.oe2403sp1.aarch64.rpm",
"nscd-2.38-98.oe2403sp1.aarch64.rpm",
"nss_modules-2.38-98.oe2403sp1.aarch64.rpm"
],
"noarch": [
"glibc-help-2.38-98.oe2403sp1.noarch.rpm"
],
"src": [
"glibc-2.38-98.oe2403sp1.src.rpm"
],
"x86_64": [
"glibc-2.38-98.oe2403sp1.x86_64.rpm",
"glibc-all-langpacks-2.38-98.oe2403sp1.x86_64.rpm",
"glibc-common-2.38-98.oe2403sp1.x86_64.rpm",
"glibc-debuginfo-2.38-98.oe2403sp1.x86_64.rpm",
"glibc-debugsource-2.38-98.oe2403sp1.x86_64.rpm",
"glibc-debugutils-2.38-98.oe2403sp1.x86_64.rpm",
"glibc-devel-2.38-98.oe2403sp1.x86_64.rpm",
"glibc-locale-archive-2.38-98.oe2403sp1.x86_64.rpm",
"glibc-locale-source-2.38-98.oe2403sp1.x86_64.rpm",
"glibc-nss-devel-2.38-98.oe2403sp1.x86_64.rpm",
"libnsl-2.38-98.oe2403sp1.x86_64.rpm",
"nscd-2.38-98.oe2403sp1.x86_64.rpm",
"nss_modules-2.38-98.oe2403sp1.x86_64.rpm"
]
},
"package": {
"ecosystem": "openEuler:24.03-LTS-SP1",
"name": "glibc",
"purl": "pkg:rpm/openEuler/glibc\u0026distro=openEuler-24.03-LTS-SP1"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "2.38-98.oe2403sp1"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"database_specific": {
"severity": "High"
},
"details": "The GNU C Library project provides the core libraries for the GNU system and GNU/Linux systems, as well as many other systems that use Linux as the kernel. These libraries provide critical APIs including ISO C11, POSIX.1-2008, BSD, OS-specific APIs and more. These APIs include such foundational facilities as open, read, write, malloc, printf, getaddrinfo, dlopen, pthread_create, crypt, login, exit and more.\r\n\r\nSecurity Fix(es):\n\nCalling gethostbyaddr or gethostbyaddr_r with a configured nsswitch.conf that specifies the library\u0026apos;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.(CVE-2026-4437)\n\nCalling gethostbyaddr or gethostbyaddr_r with a configured nsswitch.conf that specifies the library\u0026apos;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.(CVE-2026-4438)",
"id": "OESA-2026-1803",
"modified": "2026-08-06T11:10:49Z",
"published": "2026-04-03T11:10:49Z",
"references": [
{
"type": "ADVISORY",
"url": "https://www.openeuler.org/zh/security/security-bulletins/detail/?id=openEuler-SA-2026-1803"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-4437"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-4438"
}
],
"schema_version": "1.7.2",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
],
"summary": "glibc security update",
"upstream": [
"CVE-2026-4437",
"CVE-2026-4438"
]
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.