Vulnerability-Lookup

CVE-2026-4438 (GCVE-0-2026-4438)

Vulnerability from cvelistv5 – Published: 2026-03-20 19:59 – Updated: 2026-07-14 12:45

Title

gethostbyaddr and gethostbyaddr_r return invalid DNS hostnames

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.

Severity

5.4 (Medium)


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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-03-23 15:06 UTC

CWE

CWE-20 - Improper input validation
CWE-88 - Improper Neutralization of Argument Delimiters in a Command ('Argument Injection')

Assigner

glibc redhat root Scorecard

References

2 references

URL	Tags
https://sourceware.org/bugzilla/show_bug.cgi?id=34015
https://cert-portal.siemens.com/productcert/html/…

Impacted products

4 products

Vendor	Product	Version	CPE status
The GNU C Library	glibc	Affected: 2.34 , ≤ 2.43 (custom)	guessed
Siemens	SIMATIC S7-1500 CPU 1518-4 PN/DP MFP	Affected: V3.1.5 , < V3.1.6 (custom)	guessed
Siemens	SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP	Affected: V3.1.5 , < V3.1.6 (custom)	guessed
Siemens	SIPLUS S7-1500 CPU 1518-4 PN/DP MFP	Affected: V3.1.5 , < V3.1.6 (custom)	guessed

Date Public

2026-03-20 22:17

Credits

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

Show details on NVD website

JSON

To clipboard

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OESA-2026-1805 (CVE-2026-4437)

Vulnerability from osv_openeuler – Published: 2026-04-03 11:10 – Updated: 2026-08-06 11:10 – Source website

Summary

glibc security update

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.

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)

Severity

7.5 (High)


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

References

URL

Type

	https://www.openeuler.org/zh/security/security-bu…	ADVISORY
	https://nvd.nist.gov/vuln/detail/CVE-2026-4437	ADVISORY
	https://nvd.nist.gov/vuln/detail/CVE-2026-4438	ADVISORY

JSON

To clipboard

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          "glibc-all-langpacks-2.38-98.oe2403sp3.aarch64.rpm",
          "glibc-common-2.38-98.oe2403sp3.aarch64.rpm",
          "glibc-debuginfo-2.38-98.oe2403sp3.aarch64.rpm",
          "glibc-debugsource-2.38-98.oe2403sp3.aarch64.rpm",
          "glibc-debugutils-2.38-98.oe2403sp3.aarch64.rpm",
          "glibc-devel-2.38-98.oe2403sp3.aarch64.rpm",
          "glibc-locale-archive-2.38-98.oe2403sp3.aarch64.rpm",
          "glibc-locale-source-2.38-98.oe2403sp3.aarch64.rpm",
          "glibc-nss-devel-2.38-98.oe2403sp3.aarch64.rpm",
          "libnsl-2.38-98.oe2403sp3.aarch64.rpm",
          "nscd-2.38-98.oe2403sp3.aarch64.rpm",
          "nss_modules-2.38-98.oe2403sp3.aarch64.rpm"
        ],
        "noarch": [
          "glibc-help-2.38-98.oe2403sp3.noarch.rpm"
        ],
        "src": [
          "glibc-2.38-98.oe2403sp3.src.rpm"
        ],
        "x86_64": [
          "glibc-2.38-98.oe2403sp3.x86_64.rpm",
          "glibc-all-langpacks-2.38-98.oe2403sp3.x86_64.rpm",
          "glibc-common-2.38-98.oe2403sp3.x86_64.rpm",
          "glibc-debuginfo-2.38-98.oe2403sp3.x86_64.rpm",
          "glibc-debugsource-2.38-98.oe2403sp3.x86_64.rpm",
          "glibc-debugutils-2.38-98.oe2403sp3.x86_64.rpm",
          "glibc-devel-2.38-98.oe2403sp3.x86_64.rpm",
          "glibc-locale-archive-2.38-98.oe2403sp3.x86_64.rpm",
          "glibc-locale-source-2.38-98.oe2403sp3.x86_64.rpm",
          "glibc-nss-devel-2.38-98.oe2403sp3.x86_64.rpm",
          "libnsl-2.38-98.oe2403sp3.x86_64.rpm",
          "nscd-2.38-98.oe2403sp3.x86_64.rpm",
          "nss_modules-2.38-98.oe2403sp3.x86_64.rpm"
        ]
      },
      "package": {
        "ecosystem": "openEuler:24.03-LTS-SP3",
        "name": "glibc",
        "purl": "pkg:rpm/openEuler/glibc\u0026distro=openEuler-24.03-LTS-SP3"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.38-98.oe2403sp3"
            }
          ],
          "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-2026-1805",
  "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-2026-1805"
    },
    {
      "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"
  ]
}

OPENSUSE-SU-2026:10662-1

Vulnerability from csaf_opensuse - Published: 2026-04-30 00:00 - Updated: 2026-09-23 17:28

Summary

glibc-2.43-1.1 on GA media

Severity

Moderate

Scope

5 vulnerabilities in this advisory, including CVE-2026-4438.

CVE-2026-4438

4.7 (Medium)


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

Recommended: 48 products

Open the full advisory

OPENSUSE-SU-2026:20501-1

Vulnerability from csaf_opensuse - Published: 2026-04-10 06:36 - Updated: 2026-09-23 17:29

Summary

Security update for glibc

Severity

Important

Scope

2 vulnerabilities in this advisory, including CVE-2026-4438.

CVE-2026-4438

4.7 (Medium)


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

Recommended: 44 products

Open the full advisory

RHSA-2026:19061

Vulnerability from csaf_opensuse - Published: 2026-05-19 14:41 - Updated: 2026-09-29 00:22

Summary

Red Hat Security Advisory: glibc security update

Severity

Moderate

Scope

2 vulnerabilities in this advisory, including CVE-2026-4438.

CVE-2026-4438

A flaw was found in the GNU C library (glibc). When applications use the `gethostbyaddr` or `gethostbyaddr_r` functions with a `nsswitch.conf` configuration that specifies glibc's DNS backend, the library may return an invalid DNS hostname. This violates the DNS specification and could lead to applications receiving incorrect hostname information, potentially impacting network operations or security decisions.

4.0 (Medium)


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

Fixed: 993 products

https://access.redhat.com/errata/RHSA-2026:19061

Open the full advisory

RHSA-2026:20597

Vulnerability from csaf_opensuse - Published: 2026-05-26 10:23 - Updated: 2026-09-29 00:22

Summary

Red Hat Security Advisory: glibc security update

Severity

Moderate

Scope

3 vulnerabilities in this advisory, including CVE-2026-4438.

CVE-2026-4438

4.0 (Medium)


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

Fixed: 1017 products

https://access.redhat.com/errata/RHSA-2026:20597

Open the full advisory

RHSA-2026:22634

Vulnerability from csaf_redhat - Published: 2026-06-02 18:37 - Updated: 2026-09-30 16:38

Summary

Red Hat Security Advisory: Insights proxy Container Image

Severity

Important

Scope

13 vulnerabilities in this advisory, including CVE-2026-4438.

CVE-2026-4438

4.0 (Medium)


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

Fixed: 2 products

https://access.redhat.com/errata/RHSA-2026:22634

Open the full advisory

RHSA-2026:26319

Vulnerability from csaf_redhat - Published: 2026-06-16 12:37 - Updated: 2026-09-29 00:22

Summary

Red Hat Security Advisory: Red Hat Update Infrastructure 5.2 security update

Severity

Important

Scope

34 vulnerabilities in this advisory, including CVE-2026-4438.

CVE-2026-4438

4.0 (Medium)


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

Fixed: 4 products Known not affected: 1 product

https://access.redhat.com/errata/RHSA-2026:26319

Open the full advisory

RHSA-2026:27998

Vulnerability from csaf_redhat - Published: 2026-06-22 15:31 - Updated: 2026-09-29 00:22

Summary

Red Hat Security Advisory: Cost Management Metrics Operator Update

Severity

Important

Scope

7 vulnerabilities in this advisory, including CVE-2026-4438.

CVE-2026-4438

4.0 (Medium)


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

Fixed: 4 products Known not affected: 1 product

https://access.redhat.com/errata/RHSA-2026:27998

Open the full advisory

RHSA-2026:29197

Vulnerability from csaf_redhat - Published: 2026-06-24 16:29 - Updated: 2026-10-01 10:24

Summary

Red Hat Security Advisory: A Subscription Management tool for finding and reporting Red Hat product usage

Severity

Important

Scope

53 vulnerabilities in this advisory, including CVE-2026-4438.

CVE-2026-4438

4.0 (Medium)


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

Fixed: 4 products

https://access.redhat.com/errata/RHSA-2026:29197

Open the full advisory

RHSA-2026:58981

Vulnerability from csaf_redhat - Published: 2026-08-24 11:15 - Updated: 2026-10-01 12:04

Summary

Red Hat Security Advisory: Red Hat Update Infrastructure 5.3 Technology Preview security update

Severity

Critical

Scope

118 vulnerabilities in this advisory, including CVE-2026-4438.

CVE-2026-4438

4.0 (Medium)


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

Fixed: 3 products Known not affected: 1 product

https://access.redhat.com/errata/RHSA-2026:58981

Open the full advisory

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 MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
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.

Action not permitted

CVE-2026-4438 (GCVE-0-2026-4438)

OESA-2026-1805 (CVE-2026-4437)

Tags

Sightings

Nomenclature

Related by attack behaviour