ALSA-2026:19158 (CVE-2026-2291)

Vulnerability from osv_almalinux – Published: 2026-05-19 00:00 – Updated: 2026-05-26 12:28 – Source website
VLAI
Summary
Important: dnsmasq security update
Details

The dnsmasq packages contain Dnsmasq, a lightweight DNS (Domain Name Server) forwarder and DHCP (Dynamic Host Configuration Protocol) server.

Security Fix(es):

  • dnsmasq: dnsmasq: heap buffer overflow in cache via NAME_ESCAPE expansion (CVE-2026-2291)
  • dnsmasq: NSEC bitmap parsing infinite loop (CVE-2026-4890)
  • dnsmasq: RRSIG rdlen underflow leading to heap OOB read (CVE-2026-4891)
  • dnsmasq: DHCPv6 CLID buffer overflow in helper process (CVE-2026-4892)
  • dnsmasq: Broken ECS source validation bypass (CVE-2026-4893)
  • dnsmasq: extract_addresses() OOB read via malformed rdlen (CVE-2026-5172)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

References
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "AlmaLinux:10",
        "name": "dnsmasq"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.90-7.el10_2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "AlmaLinux:10",
        "name": "dnsmasq-utils"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.90-7.el10_2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "details": "The dnsmasq packages contain Dnsmasq, a lightweight DNS (Domain Name Server) forwarder and DHCP (Dynamic Host Configuration Protocol) server.  \n\nSecurity Fix(es):  \n\n  * dnsmasq: dnsmasq: heap buffer overflow in cache via NAME_ESCAPE expansion (CVE-2026-2291)\n  * dnsmasq: NSEC bitmap parsing infinite loop (CVE-2026-4890)\n  * dnsmasq: RRSIG rdlen underflow leading to heap OOB read (CVE-2026-4891)\n  * dnsmasq: DHCPv6 CLID buffer overflow in helper process (CVE-2026-4892)\n  * dnsmasq: Broken ECS source validation bypass (CVE-2026-4893)\n  * dnsmasq: extract_addresses() OOB read via malformed rdlen (CVE-2026-5172)\n\n\nFor more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.\n",
  "id": "ALSA-2026:19158",
  "modified": "2026-05-26T12:28:55Z",
  "published": "2026-05-19T00:00:00Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:19158"
    },
    {
      "type": "REPORT",
      "url": "https://access.redhat.com/security/cve/CVE-2026-2291"
    },
    {
      "type": "REPORT",
      "url": "https://access.redhat.com/security/cve/CVE-2026-4890"
    },
    {
      "type": "REPORT",
      "url": "https://access.redhat.com/security/cve/CVE-2026-4891"
    },
    {
      "type": "REPORT",
      "url": "https://access.redhat.com/security/cve/CVE-2026-4892"
    },
    {
      "type": "REPORT",
      "url": "https://access.redhat.com/security/cve/CVE-2026-4893"
    },
    {
      "type": "REPORT",
      "url": "https://access.redhat.com/security/cve/CVE-2026-5172"
    },
    {
      "type": "REPORT",
      "url": "https://bugzilla.redhat.com/2439088"
    },
    {
      "type": "REPORT",
      "url": "https://bugzilla.redhat.com/2458516"
    },
    {
      "type": "REPORT",
      "url": "https://bugzilla.redhat.com/2458517"
    },
    {
      "type": "REPORT",
      "url": "https://bugzilla.redhat.com/2458518"
    },
    {
      "type": "REPORT",
      "url": "https://bugzilla.redhat.com/2458519"
    },
    {
      "type": "REPORT",
      "url": "https://bugzilla.redhat.com/2458521"
    },
    {
      "type": "ADVISORY",
      "url": "https://errata.almalinux.org/10/ALSA-2026-19158.html"
    }
  ],
  "related": [
    "CVE-2026-2291",
    "CVE-2026-4890",
    "CVE-2026-4891",
    "CVE-2026-4892",
    "CVE-2026-4893",
    "CVE-2026-5172"
  ],
  "schema_version": "1.7.0",
  "summary": "Important: dnsmasq security update",
  "upstream": [
    "CVE-2026-2291",
    "CVE-2026-4890",
    "CVE-2026-4891",
    "CVE-2026-4892",
    "CVE-2026-4893",
    "CVE-2026-5172"
  ]
}



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