CVE-2026-8674 (GCVE-0-2026-8674)
Vulnerability from cvelistv5
Published
2026-09-17 16:54
Modified
2026-09-17 18:09
Severity ?
5.3 (Medium) - CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE
Summary
Initializing the DNS stub resolver from an /etc/resolv.conf file, or a LOCALDOMAIN environment variable, whose search list contains a domain of roughly 200 characters or more in the GNU C Library version 2.26 to 2.44 results in an assertion failure which aborts the process. The resolver truncates the search list when copying it into the fixed-size _res.defdname buffer, then asserts that the copy is consistent with the full configuration. The consistency check compared against the wrong size and did not handle a first entry that does not fit, so a correctly truncated list failed the assertion. Any process that resolves names through the library is affected, including long-running processes that reload /etc/resolv.conf on the next query after it changes. Search domains are commonly written to /etc/resolv.conf from data received over DHCP or from a VPN server, so an attacker on the local network may be able to trigger this without privileges on the target system, subject to validation by the network configuration software.
References
Impacted products
Vendor Product Version
The GNU C Library glibc Version: 2.26   <
Create a notification for this product.
Show details on NVD website

To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-8674",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-09-17T18:05:54.714741Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-09-17T18:06:00.631Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      },
      {
        "providerMetadata": {
          "dateUpdated": "2026-09-17T18:09:16.072Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "url": "http://www.openwall.com/lists/oss-security/2026/09/17/4"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "glibc",
          "vendor": "The GNU C Library",
          "versions": [
            {
              "lessThanOrEqual": "2.44",
              "status": "affected",
              "version": "2.26",
              "versionType": "custom"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "Joshua Rogers"
        }
      ],
      "datePublic": "2023-11-07T05:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "Initializing the DNS stub resolver from an /etc/resolv.conf file, or a LOCALDOMAIN environment variable, whose search list contains a domain of roughly 200 characters or more in the GNU C Library version 2.26 to 2.44 results in an assertion failure which aborts the process.\u003cbr\u003e\u003cbr\u003eThe resolver truncates the search list when copying it into the fixed-size _res.defdname buffer, then asserts that the copy is consistent with the full configuration.  The consistency check compared against the wrong size and did not handle a first entry that does not fit, so a correctly truncated list failed the assertion.  Any process that resolves names through the library is affected, including long-running processes that reload /etc/resolv.conf on the next query after it changes.  Search domains are commonly written to /etc/resolv.conf from data received over DHCP or from a VPN server, so an attacker on the local network may be able to trigger this without privileges on the target system, subject to validation by the network configuration software."
            }
          ],
          "value": "Initializing the DNS stub resolver from an /etc/resolv.conf file, or a LOCALDOMAIN environment variable, whose search list contains a domain of roughly 200 characters or more in the GNU C Library version 2.26 to 2.44 results in an assertion failure which aborts the process.\n\nThe resolver truncates the search list when copying it into the fixed-size _res.defdname buffer, then asserts that the copy is consistent with the full configuration.  The consistency check compared against the wrong size and did not handle a first entry that does not fit, so a correctly truncated list failed the assertion.  Any process that resolves names through the library is affected, including long-running processes that reload /etc/resolv.conf on the next query after it changes.  Search domains are commonly written to /etc/resolv.conf from data received over DHCP or from a VPN server, so an attacker on the local network may be able to trigger this without privileges on the target system, subject to validation by the network configuration software."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "ADJACENT_NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 5.3,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-617",
              "description": "CWE-617 Reachable Assertion",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-17T16:54:27.310Z",
        "orgId": "3ff69d7a-14f2-4f67-a097-88dee7810d18",
        "shortName": "glibc"
      },
      "references": [
        {
          "tags": [
            "issue-tracking"
          ],
          "url": "https://sourceware.org/bugzilla/show_bug.cgi?id=31026"
        },
        {
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://sourceware.org/git/?p=glibc.git;a=blob_plain;f=advisories/GLIBC-SA-2026-0021"
        },
        {
          "tags": [
            "patch"
          ],
          "url": "https://sourceware.org/git/?p=glibc.git;a=commit;h=506ea57086bfb9ce3daff1c14246a1cb532aba0a"
        },
        {
          "tags": [
            "technical-description"
          ],
          "url": "https://joshua.hu/fuzzing-glibc-libresolv"
        }
      ],
      "source": {
        "discovery": "EXTERNAL"
      },
      "title": "Assertion failure in the DNS stub resolver with a long search domain",
      "x_generator": {
        "engine": "Vulnogram 1.0.5"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "3ff69d7a-14f2-4f67-a097-88dee7810d18",
    "assignerShortName": "glibc",
    "cveId": "CVE-2026-8674",
    "datePublished": "2026-09-17T16:54:27.310Z",
    "dateReserved": "2026-05-15T12:15:59.229Z",
    "dateUpdated": "2026-09-17T18:09:16.072Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CVE Program Container\", \"references\": [{\"url\": \"http://www.openwall.com/lists/oss-security/2026/09/17/4\"}], \"providerMetadata\": {\"orgId\": \"af854a3a-2127-422b-91ae-364da2661108\", \"shortName\": \"CVE\", \"dateUpdated\": \"2026-09-17T18:09:16.072Z\"}}, {\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-8674\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-09-17T18:05:54.714741Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-09-17T18:05:57.976Z\"}}], \"cna\": {\"title\": \"Assertion failure in the DNS stub resolver with a long search domain\", \"source\": {\"discovery\": \"EXTERNAL\"}, \"credits\": [{\"lang\": \"en\", \"type\": \"finder\", \"value\": \"Joshua Rogers\"}], \"metrics\": [{\"format\": \"CVSS\", \"cvssV3_1\": {\"scope\": \"UNCHANGED\", \"version\": \"3.1\", \"baseScore\": 5.3, \"attackVector\": \"ADJACENT_NETWORK\", \"baseSeverity\": \"MEDIUM\", \"vectorString\": \"CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H\", \"integrityImpact\": \"NONE\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"HIGH\", \"availabilityImpact\": \"HIGH\", \"privilegesRequired\": \"NONE\", \"confidentialityImpact\": \"NONE\"}, \"scenarios\": [{\"lang\": \"en\", \"value\": \"GENERAL\"}]}], \"affected\": [{\"vendor\": \"The GNU C Library\", \"product\": \"glibc\", \"versions\": [{\"status\": \"affected\", \"version\": \"2.26\", \"versionType\": \"custom\", \"lessThanOrEqual\": \"2.44\"}], \"defaultStatus\": \"unaffected\"}], \"datePublic\": \"2023-11-07T05:00:00.000Z\", \"references\": [{\"url\": \"https://sourceware.org/bugzilla/show_bug.cgi?id=31026\", \"tags\": [\"issue-tracking\"]}, {\"url\": \"https://sourceware.org/git/?p=glibc.git;a=blob_plain;f=advisories/GLIBC-SA-2026-0021\", \"tags\": [\"vendor-advisory\"]}, {\"url\": \"https://sourceware.org/git/?p=glibc.git;a=commit;h=506ea57086bfb9ce3daff1c14246a1cb532aba0a\", \"tags\": [\"patch\"]}, {\"url\": \"https://joshua.hu/fuzzing-glibc-libresolv\", \"tags\": [\"technical-description\"]}], \"x_generator\": {\"engine\": \"Vulnogram 1.0.5\"}, \"descriptions\": [{\"lang\": \"en\", \"value\": \"Initializing the DNS stub resolver from an /etc/resolv.conf file, or a LOCALDOMAIN environment variable, whose search list contains a domain of roughly 200 characters or more in the GNU C Library version 2.26 to 2.44 results in an assertion failure which aborts the process.\\n\\nThe resolver truncates the search list when copying it into the fixed-size _res.defdname buffer, then asserts that the copy is consistent with the full configuration.  The consistency check compared against the wrong size and did not handle a first entry that does not fit, so a correctly truncated list failed the assertion.  Any process that resolves names through the library is affected, including long-running processes that reload /etc/resolv.conf on the next query after it changes.  Search domains are commonly written to /etc/resolv.conf from data received over DHCP or from a VPN server, so an attacker on the local network may be able to trigger this without privileges on the target system, subject to validation by the network configuration software.\", \"supportingMedia\": [{\"type\": \"text/html\", \"value\": \"Initializing the DNS stub resolver from an /etc/resolv.conf file, or a LOCALDOMAIN environment variable, whose search list contains a domain of roughly 200 characters or more in the GNU C Library version 2.26 to 2.44 results in an assertion failure which aborts the process.\u003cbr\u003e\u003cbr\u003eThe resolver truncates the search list when copying it into the fixed-size _res.defdname buffer, then asserts that the copy is consistent with the full configuration.  The consistency check compared against the wrong size and did not handle a first entry that does not fit, so a correctly truncated list failed the assertion.  Any process that resolves names through the library is affected, including long-running processes that reload /etc/resolv.conf on the next query after it changes.  Search domains are commonly written to /etc/resolv.conf from data received over DHCP or from a VPN server, so an attacker on the local network may be able to trigger this without privileges on the target system, subject to validation by the network configuration software.\", \"base64\": false}]}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-617\", \"description\": \"CWE-617 Reachable Assertion\"}]}], \"providerMetadata\": {\"orgId\": \"3ff69d7a-14f2-4f67-a097-88dee7810d18\", \"shortName\": \"glibc\", \"dateUpdated\": \"2026-09-17T16:54:27.310Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-8674\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-09-17T18:09:16.072Z\", \"dateReserved\": \"2026-05-15T12:15:59.229Z\", \"assignerOrgId\": \"3ff69d7a-14f2-4f67-a097-88dee7810d18\", \"datePublished\": \"2026-09-17T16:54:27.310Z\", \"assignerShortName\": \"glibc\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
  • Confirmed: The vulnerability is confirmed from an analyst perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
  • Patched: This vulnerability was successfully patched by the user reporting the sighting.
  • Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
  • Not confirmed: The user expresses doubt about the veracity of the vulnerability.
  • Not patched: This vulnerability was not successfully patched by the user reporting the sighting.