{
  "document": {
    "aggregate_severity": {
      "text": "Important"
    },
    "category": "csaf_security_advisory",
    "csaf_version": "2.0",
    "distribution": {
      "text": "TuxCare License Agreement",
      "tlp": {
        "label": "WHITE",
        "url": "https://www.first.org/tlp/"
      }
    },
    "lang": "en",
    "notes": [
      {
        "category": "legal_disclaimer",
        "text": "This content is licensed under the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/). If you distribute this content, or a modified version of it, you must provide attribution to Cloud Linux Inc. and provide a link to the original.",
        "title": "Terms of Use"
      },
      {
        "category": "details",
        "text": "CVE-2026-2291: fix buffer overflow in union bigname\n- CVE-2026-4890: fix NSEC bitmap parsing infinite loop and OOB reads\n- CVE-2026-4891: verify rdlen field in RRSIG packets\n- CVE-2026-4892: fix buffer overflow in helper.c with large CLIDs\n- CVE-2026-4893: fix broken client subnet validation",
        "title": "Details"
      }
    ],
    "publisher": {
      "category": "vendor",
      "contact_details": "https://tuxcare.com/contact/",
      "name": "TuxCare",
      "namespace": "https://tuxcare.com/"
    },
    "references": [
      {
        "category": "self",
        "summary": "https://cve.tuxcare.com/els/releases/CLSA-2026:1779437608",
        "url": "https://cve.tuxcare.com/els/releases/CLSA-2026:1779437608"
      },
      {
        "category": "self",
        "summary": "Canonical URL",
        "url": "https://security.tuxcare.com/csaf/v2/els_os/centos-stream8els/advisories/2026/clsa-2026_1779437608.json"
      }
    ],
    "tracking": {
      "current_release_date": "2026-05-22T08:14:17Z",
      "generator": {
        "date": "2026-05-22T08:14:17Z",
        "engine": {
          "name": "pyCSAF"
        }
      },
      "id": "CLSA-2026:1779437608",
      "initial_release_date": "2026-05-22T08:14:17Z",
      "revision_history": [
        {
          "date": "2026-05-22T08:14:17Z",
          "number": "1",
          "summary": "Initial version"
        }
      ],
      "status": "final",
      "version": "1"
    },
    "title": "dnsmasq: Fix of 5 CVEs"
  },
  "product_tree": {
    "branches": [
      {
        "branches": [
          {
            "branches": [
              {
                "category": "product_name",
                "name": "Community Enterprise Operating System 8",
                "product": {
                  "name": "Community Enterprise Operating System 8",
                  "product_id": "CentOS-Stream-8",
                  "product_identification_helper": {
                    "cpe": "cpe:2.3:o:centos:centos:8:*:*:*:*:*:*:*"
                  }
                }
              }
            ],
            "category": "product_family",
            "name": "Community Enterprise Operating System"
          }
        ],
        "category": "vendor",
        "name": "Red Hat, Inc."
      },
      {
        "branches": [
          {
            "branches": [
              {
                "category": "product_version",
                "name": "dnsmasq-utils-0:2.79-33.el8.tuxcare.els1.x86_64",
                "product": {
                  "name": "dnsmasq-utils-0:2.79-33.el8.tuxcare.els1.x86_64",
                  "product_id": "dnsmasq-utils-0:2.79-33.el8.tuxcare.els1.x86_64",
                  "product_identification_helper": {
                    "purl": "pkg:rpm/tuxcare/dnsmasq-utils@2.79-33.el8.tuxcare.els1?arch=x86_64"
                  }
                }
              },
              {
                "category": "product_version",
                "name": "dnsmasq-0:2.79-33.el8.tuxcare.els1.x86_64",
                "product": {
                  "name": "dnsmasq-0:2.79-33.el8.tuxcare.els1.x86_64",
                  "product_id": "dnsmasq-0:2.79-33.el8.tuxcare.els1.x86_64",
                  "product_identification_helper": {
                    "purl": "pkg:rpm/tuxcare/dnsmasq@2.79-33.el8.tuxcare.els1?arch=x86_64"
                  }
                }
              }
            ],
            "category": "architecture",
            "name": "x86_64"
          }
        ],
        "category": "vendor",
        "name": "TuxCare"
      }
    ],
    "relationships": [
      {
        "category": "default_component_of",
        "full_product_name": {
          "name": "dnsmasq-utils-0:2.79-33.el8.tuxcare.els1.x86_64 as a component of Community Enterprise Operating System 8",
          "product_id": "CentOS-Stream-8:dnsmasq-utils-0:2.79-33.el8.tuxcare.els1.x86_64"
        },
        "product_reference": "dnsmasq-utils-0:2.79-33.el8.tuxcare.els1.x86_64",
        "relates_to_product_reference": "CentOS-Stream-8"
      },
      {
        "category": "default_component_of",
        "full_product_name": {
          "name": "dnsmasq-0:2.79-33.el8.tuxcare.els1.x86_64 as a component of Community Enterprise Operating System 8",
          "product_id": "CentOS-Stream-8:dnsmasq-0:2.79-33.el8.tuxcare.els1.x86_64"
        },
        "product_reference": "dnsmasq-0:2.79-33.el8.tuxcare.els1.x86_64",
        "relates_to_product_reference": "CentOS-Stream-8"
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2026-2291",
      "cwe": {
        "id": "CWE-131",
        "name": "Incorrect Calculation of Buffer Size"
      },
      "notes": [
        {
          "category": "description",
          "text": "dnsmasqs extract_name() function can be abused to cause a heap buffer overflow, allowing an attacker to inject false DNS cache entries, which could result in DNS lookups to redirect to an attacker-controlled IP address, or to cause a DoS.",
          "title": "Vulnerability description"
        },
        {
          "category": "general",
          "text": "The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.",
          "title": "CVSS score applicability"
        }
      ],
      "product_status": {
        "fixed": [
          "CentOS-Stream-8:dnsmasq-0:2.79-33.el8.tuxcare.els1.x86_64",
          "CentOS-Stream-8:dnsmasq-utils-0:2.79-33.el8.tuxcare.els1.x86_64"
        ]
      },
      "references": [
        {
          "category": "self",
          "summary": "Canonical URL",
          "url": "https://cve.tuxcare.com/els/cve/CVE-2026-2291"
        }
      ],
      "release_date": "2026-05-09T00:00:00Z",
      "remediations": [
        {
          "category": "vendor_fix",
          "date": "2026-05-22T08:13:31.445856Z",
          "details": "Details on how to apply the fix are available at: https://cve.tuxcare.com/els/releases/CLSA-2026:1779437608",
          "product_ids": [
            "CentOS-Stream-8:dnsmasq-0:2.79-33.el8.tuxcare.els1.x86_64",
            "CentOS-Stream-8:dnsmasq-utils-0:2.79-33.el8.tuxcare.els1.x86_64"
          ],
          "url": "https://cve.tuxcare.com/els/releases/CLSA-2026:1779437608"
        }
      ],
      "scores": [
        {
          "cvss_v3": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 6.5,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "NONE",
            "integrityImpact": "LOW",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H",
            "version": "3.1"
          },
          "products": [
            "CentOS-Stream-8:dnsmasq-0:2.79-33.el8.tuxcare.els1.x86_64",
            "CentOS-Stream-8:dnsmasq-utils-0:2.79-33.el8.tuxcare.els1.x86_64"
          ]
        }
      ],
      "threats": [
        {
          "category": "impact",
          "details": "Moderate"
        }
      ]
    },
    {
      "cve": "CVE-2026-4891",
      "cwe": {
        "id": "CWE-125",
        "name": "Out-of-bounds Read"
      },
      "notes": [
        {
          "category": "description",
          "text": "A heap out-of-bounds read vulnerability was discovered in dnsmasq's DNSSEC validation. When processing RRSIG records, dnsmasq calculates the signature length by subtracting the fixed field size from the record's declared data length. A crafted RRSIG record with a data length smaller than the fixed fields causes this calculation to underflow, potentially resulting in an out-of-bounds read and process crash.",
          "title": "Vulnerability description"
        },
        {
          "category": "general",
          "text": "The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.",
          "title": "CVSS score applicability"
        }
      ],
      "product_status": {
        "fixed": [
          "CentOS-Stream-8:dnsmasq-0:2.79-33.el8.tuxcare.els1.x86_64",
          "CentOS-Stream-8:dnsmasq-utils-0:2.79-33.el8.tuxcare.els1.x86_64"
        ]
      },
      "references": [
        {
          "category": "self",
          "summary": "Canonical URL",
          "url": "https://cve.tuxcare.com/els/cve/CVE-2026-4891"
        }
      ],
      "release_date": "2026-05-09T00:00:00Z",
      "remediations": [
        {
          "category": "vendor_fix",
          "date": "2026-05-22T08:13:31.445856Z",
          "details": "Details on how to apply the fix are available at: https://cve.tuxcare.com/els/releases/CLSA-2026:1779437608",
          "product_ids": [
            "CentOS-Stream-8:dnsmasq-0:2.79-33.el8.tuxcare.els1.x86_64",
            "CentOS-Stream-8:dnsmasq-utils-0:2.79-33.el8.tuxcare.els1.x86_64"
          ],
          "url": "https://cve.tuxcare.com/els/releases/CLSA-2026:1779437608"
        }
      ],
      "scores": [
        {
          "cvss_v3": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          },
          "products": [
            "CentOS-Stream-8:dnsmasq-0:2.79-33.el8.tuxcare.els1.x86_64",
            "CentOS-Stream-8:dnsmasq-utils-0:2.79-33.el8.tuxcare.els1.x86_64"
          ]
        }
      ],
      "threats": [
        {
          "category": "impact",
          "details": "Important"
        }
      ]
    },
    {
      "cve": "CVE-2026-4892",
      "cwe": {
        "id": "CWE-122",
        "name": "Heap-based Buffer Overflow"
      },
      "notes": [
        {
          "category": "description",
          "text": "A heap buffer overflow was discovered in dnsmasq's DHCP script helper process. When processing DHCPv6 client identifiers (CLIDs), the helper hex-encodes the raw CLID bytes into a fixed-size buffer without length validation. Since DHCPv6 CLIDs can be up to 65,535 bytes, a crafted DHCPv6 packet can overflow the buffer with attacker-controlled content. The helper process runs with root privileges.",
          "title": "Vulnerability description"
        },
        {
          "category": "general",
          "text": "The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.",
          "title": "CVSS score applicability"
        }
      ],
      "product_status": {
        "fixed": [
          "CentOS-Stream-8:dnsmasq-0:2.79-33.el8.tuxcare.els1.x86_64",
          "CentOS-Stream-8:dnsmasq-utils-0:2.79-33.el8.tuxcare.els1.x86_64"
        ]
      },
      "references": [
        {
          "category": "self",
          "summary": "Canonical URL",
          "url": "https://cve.tuxcare.com/els/cve/CVE-2026-4892"
        }
      ],
      "release_date": "2026-05-09T00:00:00Z",
      "remediations": [
        {
          "category": "vendor_fix",
          "date": "2026-05-22T08:13:31.445856Z",
          "details": "Details on how to apply the fix are available at: https://cve.tuxcare.com/els/releases/CLSA-2026:1779437608",
          "product_ids": [
            "CentOS-Stream-8:dnsmasq-0:2.79-33.el8.tuxcare.els1.x86_64",
            "CentOS-Stream-8:dnsmasq-utils-0:2.79-33.el8.tuxcare.els1.x86_64"
          ],
          "url": "https://cve.tuxcare.com/els/releases/CLSA-2026:1779437608"
        }
      ],
      "scores": [
        {
          "cvss_v3": {
            "attackComplexity": "LOW",
            "attackVector": "ADJACENT_NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 8.8,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "products": [
            "CentOS-Stream-8:dnsmasq-0:2.79-33.el8.tuxcare.els1.x86_64",
            "CentOS-Stream-8:dnsmasq-utils-0:2.79-33.el8.tuxcare.els1.x86_64"
          ]
        }
      ],
      "threats": [
        {
          "category": "impact",
          "details": "Important"
        }
      ]
    },
    {
      "cve": "CVE-2026-4890",
      "cwe": {
        "id": "CWE-835",
        "name": "Loop with Unreachable Exit Condition ('Infinite Loop')"
      },
      "notes": [
        {
          "category": "description",
          "text": "A denial of service vulnerability was discovered in dnsmasq's DNSSEC validation. When parsing NSEC and NSEC3 bitmap records, the window iteration logic fails to account for the 2-byte window header when advancing through the bitmap data. A specially crafted DNS response with a zero-length bitmap can cause an infinite loop, making dnsmasq unresponsive to all queries.",
          "title": "Vulnerability description"
        },
        {
          "category": "general",
          "text": "The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.",
          "title": "CVSS score applicability"
        }
      ],
      "product_status": {
        "fixed": [
          "CentOS-Stream-8:dnsmasq-0:2.79-33.el8.tuxcare.els1.x86_64",
          "CentOS-Stream-8:dnsmasq-utils-0:2.79-33.el8.tuxcare.els1.x86_64"
        ]
      },
      "references": [
        {
          "category": "self",
          "summary": "Canonical URL",
          "url": "https://cve.tuxcare.com/els/cve/CVE-2026-4890"
        }
      ],
      "release_date": "2026-05-09T00:00:00Z",
      "remediations": [
        {
          "category": "vendor_fix",
          "date": "2026-05-22T08:13:31.445856Z",
          "details": "Details on how to apply the fix are available at: https://cve.tuxcare.com/els/releases/CLSA-2026:1779437608",
          "product_ids": [
            "CentOS-Stream-8:dnsmasq-0:2.79-33.el8.tuxcare.els1.x86_64",
            "CentOS-Stream-8:dnsmasq-utils-0:2.79-33.el8.tuxcare.els1.x86_64"
          ],
          "url": "https://cve.tuxcare.com/els/releases/CLSA-2026:1779437608"
        }
      ],
      "scores": [
        {
          "cvss_v3": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          },
          "products": [
            "CentOS-Stream-8:dnsmasq-0:2.79-33.el8.tuxcare.els1.x86_64",
            "CentOS-Stream-8:dnsmasq-utils-0:2.79-33.el8.tuxcare.els1.x86_64"
          ]
        }
      ],
      "threats": [
        {
          "category": "impact",
          "details": "Important"
        }
      ]
    },
    {
      "cve": "CVE-2026-4893",
      "cwe": {
        "id": "CWE-20",
        "name": "Improper Input Validation"
      },
      "notes": [
        {
          "category": "description",
          "text": "A validation bypass was discovered in dnsmasq's RFC 7871 client subnet (ECS) handling. When verifying ECS source information in DNS responses, dnsmasq passes the OPT record length instead of the full packet length to the validation function.This causes all internal bounds checks to fail, completely bypassing ECS source validation and allowing an attacker to spoof client subnet information.",
          "title": "Vulnerability description"
        },
        {
          "category": "general",
          "text": "The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.",
          "title": "CVSS score applicability"
        }
      ],
      "product_status": {
        "fixed": [
          "CentOS-Stream-8:dnsmasq-0:2.79-33.el8.tuxcare.els1.x86_64",
          "CentOS-Stream-8:dnsmasq-utils-0:2.79-33.el8.tuxcare.els1.x86_64"
        ]
      },
      "references": [
        {
          "category": "self",
          "summary": "Canonical URL",
          "url": "https://cve.tuxcare.com/els/cve/CVE-2026-4893"
        }
      ],
      "release_date": "2026-05-09T00:00:00Z",
      "remediations": [
        {
          "category": "vendor_fix",
          "date": "2026-05-22T08:13:31.445856Z",
          "details": "Details on how to apply the fix are available at: https://cve.tuxcare.com/els/releases/CLSA-2026:1779437608",
          "product_ids": [
            "CentOS-Stream-8:dnsmasq-0:2.79-33.el8.tuxcare.els1.x86_64",
            "CentOS-Stream-8:dnsmasq-utils-0:2.79-33.el8.tuxcare.els1.x86_64"
          ],
          "url": "https://cve.tuxcare.com/els/releases/CLSA-2026:1779437608"
        }
      ],
      "scores": [
        {
          "cvss_v3": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 6.5,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "LOW",
            "integrityImpact": "LOW",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N",
            "version": "3.1"
          },
          "products": [
            "CentOS-Stream-8:dnsmasq-0:2.79-33.el8.tuxcare.els1.x86_64",
            "CentOS-Stream-8:dnsmasq-utils-0:2.79-33.el8.tuxcare.els1.x86_64"
          ]
        }
      ],
      "threats": [
        {
          "category": "impact",
          "details": "Moderate"
        }
      ]
    }
  ]
}