Vulnerability-Lookup

CVE-2026-64194 (GCVE-0-2026-64194)

Vulnerability from cvelistv5 – Published: 2026-07-20 17:55 – Updated: 2026-07-21 18:56

Title

Net::DNS versions through 1.55 for Perl allow Denial of Service via deep DNS compression pointer chains

Summary

Net::DNS versions through 1.55 for Perl allow Denial of Service via deep DNS compression pointer chains. Net::DNS::DomainName::decode follows RFC 1035 compression pointers by recursing into itself with no depth limit. It is possible to construct a name which saturates the call stack (at least with larger TCP responses), leading to a potential Denial of Service. The guard `$link < $offset` prevents forward and circular chains, but still allows arbitrarily long backward chains. The per-offset cache (`$cache`) is populated at the start of each call and short-circuits only re-traverses of the same offset - the initial descent through a fresh chain still recurses at full depth. A crafted packet can chain two-byte compression pointers so that each one points two bytes earlier than the previous, producing a chain length of `offset / 2`. For the 14-bit pointer field (max offset 16383) this gives up to ~8191 recursive frames. For a TCP DNS message the limit is the 16-bit length field (~32767 frames). Perl's default C stack handles only a few thousand frames; beyond that the process receives SIGSEGV or similar, which is a denial-of-service for any application parsing untrusted DNS data. The vulnerability is triggered by `Net::DNS::Packet->new(\$wire)` i.e. any point where the library decodes a DNS message from the network.

Severity

7.5 (High)


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

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator (v2.0.3)

CWE

CWE-674 - Uncontrolled Recursion

Assigner

CPANSec

References

4 references

URL	Tags
https://www.net-dns.org/blog/#release-candidate-f…
https://rt.cpan.org/Ticket/Display.html?id=179946	issue-tracking
https://metacpan.org/release/NLNETLABS/Net-DNS-1.…	release-notes
http://www.openwall.com/lists/oss-security/2026/0…

Impacted products

1 product

Vendor	Product	Version
NLNETLABS	Net::DNS	Affected: 0 , ≤ 1.55 (custom)

Credits

Steffen Ullrich

Show details on NVD website

JSON

To clipboard

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FKIE_CVE-2026-64194

Vulnerability from fkie_nvd - Published: 2026-07-20 19:17 - Updated: 2026-07-21 19:35

Severity

7.5 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Summary

References

	URL	Tags
	9b29abf9-4ab0-4765-b253-1875cd9b441e	https://metacpan.org/release/NLNETLABS/Net-DNS-1.55_01/changes
	9b29abf9-4ab0-4765-b253-1875cd9b441e	https://rt.cpan.org/Ticket/Display.html?id=179946
	9b29abf9-4ab0-4765-b253-1875cd9b441e	https://www.net-dns.org/blog/#release-candidate-for-netdns-1.56
	af854a3a-2127-422b-91ae-364da2661108	http://www.openwall.com/lists/oss-security/2026/07/20/13

Impacted products

	Vendor	Product	Version

JSON

To clipboard

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      "affectedData": [
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          "collectionURL": "https://cpan.org/modules",
          "defaultStatus": "unaffected",
          "packageName": "Net-DNS",
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GHSA-M3GJ-74X3-VC94

Vulnerability from github – Published: 2026-07-20 21:31 – Updated: 2026-07-21 21:32

Details

Net::DNS versions through 1.55 for Perl allow Denial of Service via deep DNS compression pointer chains.

Net::DNS::DomainName::decode follows RFC 1035 compression pointers by recursing into itself with no depth limit. It is possible to construct a name which saturates the call stack (at least with larger TCP responses), leading to a potential Denial of Service.

The guard $link < $offset prevents forward and circular chains, but still allows arbitrarily long backward chains. The per-offset cache ($cache) is populated at the start of each call and short-circuits only re-traverses of the same offset - the initial descent through a fresh chain still recurses at full depth.

A crafted packet can chain two-byte compression pointers so that each one points two bytes earlier than the previous, producing a chain length of offset / 2. For the 14-bit pointer field (max offset 16383) this gives up to ~8191 recursive frames. For a TCP DNS message the limit is the 16-bit length field (~32767 frames). Perl's default C stack handles only a few thousand frames; beyond that the process receives SIGSEGV or similar, which is a denial-of-service for any application parsing untrusted DNS data.

The vulnerability is triggered by Net::DNS::Packet->new(\$wire) i.e. any point where the library decodes a DNS message from the network.

Severity

7.5 (High)


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

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-64194"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-674"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-20T19:17:30Z",
    "severity": "HIGH"
  },
  "details": "Net::DNS versions through 1.55 for Perl allow Denial of Service via deep DNS compression pointer chains.\n\nNet::DNS::DomainName::decode follows RFC 1035 compression pointers by recursing into itself with no depth limit. It is possible to construct a name which saturates the call stack (at least with larger TCP responses), leading to a potential Denial of Service.\n\nThe guard `$link \u003c $offset` prevents forward and circular chains, but still allows arbitrarily long backward chains. The per-offset cache (`$cache`) is populated at the start of each call and short-circuits only re-traverses of the same offset - the initial descent through a fresh chain still recurses at full depth.\n\nA crafted packet can chain two-byte compression pointers so that each one points two bytes earlier than the previous, producing a chain length of `offset / 2`. For the 14-bit pointer field (max offset 16383) this gives up to ~8191 recursive frames. For a TCP DNS message the limit is the 16-bit length field (~32767 frames). Perl\u0027s default C stack handles only a few thousand frames; beyond that the process receives SIGSEGV or similar, which is a denial-of-service for any application parsing untrusted DNS data.\n\nThe vulnerability is triggered by `Net::DNS::Packet-\u003enew(\\$wire)` i.e. any point where the library decodes a DNS message from the network.",
  "id": "GHSA-m3gj-74x3-vc94",
  "modified": "2026-07-21T21:32:24Z",
  "published": "2026-07-20T21:31:50Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64194"
    },
    {
      "type": "WEB",
      "url": "https://metacpan.org/release/NLNETLABS/Net-DNS-1.55_01/changes"
    },
    {
      "type": "WEB",
      "url": "https://rt.cpan.org/Ticket/Display.html?id=179946"
    },
    {
      "type": "WEB",
      "url": "https://www.net-dns.org/blog/#release-candidate-for-netdns-1.56"
    },
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2026/07/20/13"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}

ubuntu-cve-2026-64194

Vulnerability from osv_ubuntu

Published

2026-07-21 00:00

Modified

2026-07-21 00:00

Summary

Details

(Net::DNS versions through 1.55 for Perl allow Denial of Service via de ...)

Severity

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-64194	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-64194	REPORT
	https://lists.security.metacpan.org/cve-announce/…	REPORT
	https://rt.cpan.org/Ticket/Display.html?id=179946	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libnet-dns-perl",
            "binary_version": "0.68-1.2build1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:14.04:LTS",
        "name": "libnet-dns-perl",
        "purl": "pkg:deb/ubuntu/libnet-dns-perl@0.68-1.2build1?arch=source\u0026distro=trusty"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.68-1.2",
        "0.68-1.2build1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libnet-dns-perl",
            "binary_version": "0.81-2build1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:16.04:LTS",
        "name": "libnet-dns-perl",
        "purl": "pkg:deb/ubuntu/libnet-dns-perl@0.81-2build1?arch=source\u0026distro=xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.81-2",
        "0.81-2build1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libnet-dns-perl",
            "binary_version": "1.10-2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:18.04:LTS",
        "name": "libnet-dns-perl",
        "purl": "pkg:deb/ubuntu/libnet-dns-perl@1.10-2?arch=source\u0026distro=bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.10-2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libnet-dns-perl",
            "binary_version": "1.22-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "libnet-dns-perl",
        "purl": "pkg:deb/ubuntu/libnet-dns-perl@1.22-1?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.20-1",
        "1.21-1",
        "1.22-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libnet-dns-perl",
            "binary_version": "1.33-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "libnet-dns-perl",
        "purl": "pkg:deb/ubuntu/libnet-dns-perl@1.33-1?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.29-1",
        "1.32-1",
        "1.33-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libnet-dns-perl",
            "binary_version": "1.44-1ubuntu1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "libnet-dns-perl",
        "purl": "pkg:deb/ubuntu/libnet-dns-perl@1.44-1ubuntu1?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.39-2ubuntu1",
        "1.40-1ubuntu1",
        "1.44-1ubuntu1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libnet-dns-perl",
            "binary_version": "1.54-1ubuntu1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "libnet-dns-perl",
        "purl": "pkg:deb/ubuntu/libnet-dns-perl@1.54-1ubuntu1?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.50-1ubuntu1",
        "1.53-1ubuntu1",
        "1.54-1ubuntu1"
      ]
    }
  ],
  "aliases": [],
  "details": "(Net::DNS versions through 1.55 for Perl allow Denial of Service via de ...)",
  "id": "UBUNTU-CVE-2026-64194",
  "modified": "2026-07-21T00:00:00Z",
  "published": "2026-07-21T00:00:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-64194"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-64194"
    },
    {
      "type": "REPORT",
      "url": "https://lists.security.metacpan.org/cve-announce/msg/41989541/"
    },
    {
      "type": "REPORT",
      "url": "https://rt.cpan.org/Ticket/Display.html?id=179946"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-64194"
  ]
}

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.

Detection rules are retrieved from Rulezet.

Action not permitted

CVE-2026-64194 (GCVE-0-2026-64194)

FKIE_CVE-2026-64194

GHSA-M3GJ-74X3-VC94

ubuntu-cve-2026-64194

Vulnerability from osv_ubuntu

Tags

Sightings

Nomenclature