Vulnerability-Lookup

UBUNTU-CVE-2026-87078 (CVE-2026-87078)

Vulnerability from osv_ubuntu – Published: 2026-09-22 08:16 – Updated: 2026-09-23 23:36 – Source website

Details

Net::IDN::Punycode versions from 2.302 before 2.590 for Perl leak the output buffer on every rejected label in decode_punycode. The XS backend allocates the scalar it returns before it validates the input, sizing the buffer at twice the input length. The scalar is released only on the success path, so each of the three croaks that reject a label leaves the scalar and its buffer allocated. Nothing bounds the label length in the to-Unicode direction, since the 63-byte DNS limit is checked only when converting to ASCII. Only the XS backend is affected. A sender who supplies invalid labels grows the process by twice the label length per rejected call, with no successful call needed.

Severity

9.1 (Critical)


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

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-87078	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-87078	REPORT
	https://lists.security.metacpan.org/cve-announce/…	REPORT
	https://github.com/robrwo/Net-IDN-Encode/commit/9…	REPORT
	https://github.com/robrwo/Net-IDN-Encode/commit/e…	REPORT
	https://metacpan.org/release/PJCJ/Net-IDN-Encode-…	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libnet-idn-encode-perl",
            "binary_version": "2.300-1build1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:16.04:LTS",
        "name": "libnet-idn-encode-perl",
        "purl": "pkg:deb/ubuntu/libnet-idn-encode-perl@2.300-1build1?arch=source\u0026distro=xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.202-1",
        "2.300-1",
        "2.300-1build1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libnet-idn-encode-perl",
            "binary_version": "2.400-1build1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:18.04:LTS",
        "name": "libnet-idn-encode-perl",
        "purl": "pkg:deb/ubuntu/libnet-idn-encode-perl@2.400-1build1?arch=source\u0026distro=bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.400-1build1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libnet-idn-encode-perl",
            "binary_version": "2.500-1build1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "libnet-idn-encode-perl",
        "purl": "pkg:deb/ubuntu/libnet-idn-encode-perl@2.500-1build1?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.500-1",
        "2.500-1build1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libnet-idn-encode-perl",
            "binary_version": "2.500-2build1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "libnet-idn-encode-perl",
        "purl": "pkg:deb/ubuntu/libnet-idn-encode-perl@2.500-2build1?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.500-1build2",
        "2.500-2",
        "2.500-2build1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libnet-idn-encode-perl",
            "binary_version": "2.500-5"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "libnet-idn-encode-perl",
        "purl": "pkg:deb/ubuntu/libnet-idn-encode-perl@2.500-5?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.500-3",
        "2.500-3build1",
        "2.500-3build2",
        "2.500-5"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libnet-idn-encode-perl",
            "binary_version": "2.500-5build1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "libnet-idn-encode-perl",
        "purl": "pkg:deb/ubuntu/libnet-idn-encode-perl@2.500-5build1?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.500-5build1"
      ]
    }
  ],
  "aliases": [],
  "details": "Net::IDN::Punycode versions from 2.302 before 2.590 for Perl leak the output buffer on every rejected label in decode_punycode. The XS backend allocates the scalar it returns before it validates the input, sizing the buffer at twice the input length. The scalar is released only on the success path, so each of the three croaks that reject a label leaves the scalar and its buffer allocated. Nothing bounds the label length in the to-Unicode direction, since the 63-byte DNS limit is checked only when converting to ASCII. Only the XS backend is affected. A sender who supplies invalid labels grows the process by twice the label length per rejected call, with no successful call needed.",
  "id": "UBUNTU-CVE-2026-87078",
  "modified": "2026-09-23T23:36:45Z",
  "published": "2026-09-22T08:16:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-87078"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-87078"
    },
    {
      "type": "REPORT",
      "url": "https://lists.security.metacpan.org/cve-announce/msg/43753020/"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/robrwo/Net-IDN-Encode/commit/92572f726e48af5559de4cc8a831463b79dfb217.patch"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/robrwo/Net-IDN-Encode/commit/edad63e0eeeeb18d93bc6dfe4d9dcdff9c244e1b.patch"
    },
    {
      "type": "REPORT",
      "url": "https://metacpan.org/release/PJCJ/Net-IDN-Encode-2.590-TRIAL/changes"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-87078"
  ]
}

CVE-2026-87078 (GCVE-0-2026-87078)

Vulnerability from cvelistv5 – Published: 2026-09-22 07:19 – Updated: 2026-09-22 17:07

Title

Net::IDN::Punycode versions from 2.302 before 2.590 for Perl leak the output buffer on every rejected label in decode_punycode

Summary

Severity

9.1 (Critical)


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

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-09-22 12:33 UTC

CWE

CWE-401 - Missing Release of Memory after Effective Lifetime

Assigner

CPANSec redhat root

References

4 references

URL	Tags
https://metacpan.org/release/PJCJ/Net-IDN-Encode-…	release-notes
https://github.com/robrwo/Net-IDN-Encode/commit/9…	patch
https://github.com/robrwo/Net-IDN-Encode/commit/e…	patch
http://www.openwall.com/lists/oss-security/2026/0…

Impacted products

1 product

Vendor	Product	Version
		Affected: 2.302 , < 2.590 (custom)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "NETWORK",
              "availabilityImpact": "HIGH",
              "baseScore": 9.1,
              "baseSeverity": "CRITICAL",
              "confidentialityImpact": "HIGH",
              "integrityImpact": "NONE",
              "privilegesRequired": "NONE",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H",
              "version": "3.1"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2026-87078",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-09-22T12:33:13.035011Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-09-22T12:33:22.356Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      },
      {
        "providerMetadata": {
          "dateUpdated": "2026-09-22T17:07:27.357Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "url": "http://www.openwall.com/lists/oss-security/2026/09/22/13"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "collectionURL": "https://cpan.org/modules",
          "defaultStatus": "unaffected",
          "modules": [
            "Net::IDN::Punycode"
          ],
          "packageName": "Net-IDN-Encode",
          "packageURL": "pkg:cpan/Net-IDN-Encode",
          "programFiles": [
            "lib/Net/IDN/Punycode.xs"
          ],
          "programRoutines": [
            {
              "name": "Net::IDN::Punycode::decode_punycode"
            }
          ],
          "repo": "https://github.com/robrwo/Net-IDN-Encode",
          "versions": [
            {
              "lessThan": "2.590",
              "status": "affected",
              "version": "2.302",
              "versionType": "custom"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Net::IDN::Punycode versions from 2.302 before 2.590 for Perl leak the output buffer on every rejected label in decode_punycode.\n\nThe XS backend allocates the scalar it returns before it validates the input, sizing the buffer at twice the input length. The scalar is released only on the success path, so each of the three croaks that reject a label leaves the scalar and its buffer allocated. Nothing bounds the label length in the to-Unicode direction, since the 63-byte DNS limit is checked only when converting to ASCII.\n\nOnly the XS backend is affected.\n\nA sender who supplies invalid labels grows the process by twice the label length per rejected call, with no successful call needed."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-401",
              "description": "CWE-401 Missing Release of Memory after Effective Lifetime",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-22T07:19:33.195Z",
        "orgId": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
        "shortName": "CPANSec"
      },
      "references": [
        {
          "tags": [
            "release-notes"
          ],
          "url": "https://metacpan.org/release/PJCJ/Net-IDN-Encode-2.590-TRIAL/changes"
        },
        {
          "tags": [
            "patch"
          ],
          "url": "https://github.com/robrwo/Net-IDN-Encode/commit/92572f726e48af5559de4cc8a831463b79dfb217.patch"
        },
        {
          "tags": [
            "patch"
          ],
          "url": "https://github.com/robrwo/Net-IDN-Encode/commit/edad63e0eeeeb18d93bc6dfe4d9dcdff9c244e1b.patch"
        }
      ],
      "solutions": [
        {
          "lang": "en",
          "value": "Upgrade to Net-IDN-Encode 2.590-TRIAL or later."
        }
      ],
      "source": {
        "discovery": "UNKNOWN"
      },
      "timeline": [
        {
          "lang": "en",
          "time": "2016-12-07T00:00:00.000Z",
          "value": "Version 2.302 released, introducing the defect."
        },
        {
          "lang": "en",
          "time": "2026-09-17T00:00:00.000Z",
          "value": "Version 2.590-TRIAL released with fix."
        }
      ],
      "title": "Net::IDN::Punycode versions from 2.302 before 2.590 for Perl leak the output buffer on every rejected label in decode_punycode",
      "x_generator": {
        "engine": "cpansec-cna-tool 0.1"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
    "assignerShortName": "CPANSec",
    "cveId": "CVE-2026-87078",
    "datePublished": "2026-09-22T07:19:33.195Z",
    "dateReserved": "2026-09-08T19:22:20.005Z",
    "dateUpdated": "2026-09-22T17:07:27.357Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

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Confirmed: The vulnerability has been validated from an analyst's perspective.
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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.
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Action not permitted

UBUNTU-CVE-2026-87078 (CVE-2026-87078)

CVE-2026-87078 (GCVE-0-2026-87078)

Tags

Sightings

Nomenclature

Related by attack behaviour