Vulnerability-Lookup

CVE-2026-74766 (GCVE-0-2026-74766)

Vulnerability from cvelistv5 – Published: 2026-09-22 07:19 – Updated: 2026-09-22 12:41

Title

Net::IDN::Punycode versions from 2.301 before 2.590 for Perl allow a heap use-after-free via a decoded code point that reallocates the output buffer in decode_punycode

Summary

Net::IDN::Punycode versions from 2.301 before 2.590 for Perl allow a heap use-after-free via a decoded code point that reallocates the output buffer in decode_punycode. The XS backend inserts each decoded code point into the string buffer of the scalar it returns. decode_punycode computes the insertion pointer first and only then grows the buffer when the code point does not fit. The growth reallocates the buffer and updates every pointer except the insertion pointer, so the move that follows and the write of the code point go through a freed pointer. The buffer starts at twice the label length, and a code point above U+FFFF takes four bytes in the output, so a label of such code points outgrows it and forces the reallocation. Version 2.301, the fix for CVE-2016-15059, introduced the defect. Only the XS backend is affected. Decoding an attacker-supplied punycode label reads and writes freed heap memory.

Severity

8.4 (High)


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

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-09-22 12:41 UTC

CWE

CWE-416 - Use After Free

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/2…	patch
https://github.com/robrwo/Net-IDN-Encode/commit/2…	patch
https://www.cve.org/CVERecord?id=CVE-2016-15059	related

Impacted products

1 product

Vendor	Product	Version	CPE status
		Affected: 2.301 , < 2.590 (custom)

Show details on NVD website

JSON

To clipboard

{
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              "attackVector": "LOCAL",
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    "dateReserved": "2026-08-15T21:52:57.406Z",
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}

FKIE_CVE-2026-74766

Vulnerability from fkie_nvd - Published: 2026-09-22 08:16 - Updated: 2026-09-22 19:07

Severity

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

Summary

References

	URL	Tags
	9b29abf9-4ab0-4765-b253-1875cd9b441e	https://github.com/robrwo/Net-IDN-Encode/commit/259e74c5739175b063c5393a4ce4a0705678ba61.patch
	9b29abf9-4ab0-4765-b253-1875cd9b441e	https://github.com/robrwo/Net-IDN-Encode/commit/2fbc71e4d8517ab65c5d5d35fda086371b735a3f.patch
	9b29abf9-4ab0-4765-b253-1875cd9b441e	https://metacpan.org/release/PJCJ/Net-IDN-Encode-2.590-TRIAL/changes
	9b29abf9-4ab0-4765-b253-1875cd9b441e	https://www.cve.org/CVERecord?id=CVE-2016-15059

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "collectionURL": "https://cpan.org/modules",
          "defaultStatus": "unaffected",
          "modules": [
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      "url": "https://metacpan.org/release/PJCJ/Net-IDN-Encode-2.590-TRIAL/changes"
    },
    {
      "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
      "url": "https://www.cve.org/CVERecord?id=CVE-2016-15059"
    }
  ],
  "sourceIdentifier": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-416"
        }
      ],
      "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
      "type": "Secondary"
    }
  ]
}

GHSA-QFFM-J59F-77QW

Vulnerability from github – Published: 2026-09-22 09:31 – Updated: 2026-09-22 15:32

Details

Net::IDN::Punycode versions from 2.301 before 2.590 for Perl allow a heap use-after-free via a decoded code point that reallocates the output buffer in decode_punycode.

The XS backend inserts each decoded code point into the string buffer of the scalar it returns. decode_punycode computes the insertion pointer first and only then grows the buffer when the code point does not fit. The growth reallocates the buffer and updates every pointer except the insertion pointer, so the move that follows and the write of the code point go through a freed pointer. The buffer starts at twice the label length, and a code point above U+FFFF takes four bytes in the output, so a label of such code points outgrows it and forces the reallocation.

Version 2.301, the fix for CVE-2016-15059, introduced the defect. Only the XS backend is affected.

Decoding an attacker-supplied punycode label reads and writes freed heap memory.

Severity

8.4 (High)


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

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-74766"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-416"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-22T08:16:40Z",
    "severity": "HIGH"
  },
  "details": "Net::IDN::Punycode versions from 2.301 before 2.590 for Perl allow a heap use-after-free via a decoded code point that reallocates the output buffer in decode_punycode.\n\nThe XS backend inserts each decoded code point into the string buffer of the scalar it returns. decode_punycode computes the insertion pointer first and only then grows the buffer when the code point does not fit. The growth reallocates the buffer and updates every pointer except the insertion pointer, so the move that follows and the write of the code point go through a freed pointer. The buffer starts at twice the label length, and a code point above U+FFFF takes four bytes in the output, so a label of such code points outgrows it and forces the reallocation.\n\nVersion 2.301, the fix for CVE-2016-15059, introduced the defect. Only the XS backend is affected.\n\nDecoding an attacker-supplied punycode label reads and writes freed heap memory.",
  "id": "GHSA-qffm-j59f-77qw",
  "modified": "2026-09-22T15:32:32Z",
  "published": "2026-09-22T09:31:12Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-74766"
    },
    {
      "type": "WEB",
      "url": "https://github.com/robrwo/Net-IDN-Encode/commit/259e74c5739175b063c5393a4ce4a0705678ba61.patch"
    },
    {
      "type": "WEB",
      "url": "https://github.com/robrwo/Net-IDN-Encode/commit/2fbc71e4d8517ab65c5d5d35fda086371b735a3f.patch"
    },
    {
      "type": "WEB",
      "url": "https://metacpan.org/release/PJCJ/Net-IDN-Encode-2.590-TRIAL/changes"
    },
    {
      "type": "WEB",
      "url": "https://www.cve.org/CVERecord?id=CVE-2016-15059"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

UBUNTU-CVE-2026-74766 (CVE-2026-74766)

Vulnerability from osv_ubuntu – Published: 2026-09-22 00:00 – Updated: 2026-09-22 00:00 – Source website

Details

Severity

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-74766	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-74766	REPORT
	https://lists.security.metacpan.org/cve-announce/…	REPORT
	https://github.com/robrwo/Net-IDN-Encode/commit/2…	REPORT
	https://github.com/robrwo/Net-IDN-Encode/commit/2…	REPORT
	https://metacpan.org/release/PJCJ/Net-IDN-Encode-…	REPORT
	https://www.cve.org/CVERecord?id=CVE-2016-15059	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 2.301 before 2.590 for Perl allow a heap use-after-free via a decoded code point that reallocates the output buffer in decode_punycode. The XS backend inserts each decoded code point into the string buffer of the scalar it returns. decode_punycode computes the insertion pointer first and only then grows the buffer when the code point does not fit. The growth reallocates the buffer and updates every pointer except the insertion pointer, so the move that follows and the write of the code point go through a freed pointer. The buffer starts at twice the label length, and a code point above U+FFFF takes four bytes in the output, so a label of such code points outgrows it and forces the reallocation. Version 2.301, the fix for CVE-2016-15059, introduced the defect. Only the XS backend is affected. Decoding an attacker-supplied punycode label reads and writes freed heap memory.",
  "id": "UBUNTU-CVE-2026-74766",
  "modified": "2026-09-22T00:00:00Z",
  "published": "2026-09-22T00:00:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-74766"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-74766"
    },
    {
      "type": "REPORT",
      "url": "https://lists.security.metacpan.org/cve-announce/msg/43753027/"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/robrwo/Net-IDN-Encode/commit/259e74c5739175b063c5393a4ce4a0705678ba61.patch"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/robrwo/Net-IDN-Encode/commit/2fbc71e4d8517ab65c5d5d35fda086371b735a3f.patch"
    },
    {
      "type": "REPORT",
      "url": "https://metacpan.org/release/PJCJ/Net-IDN-Encode-2.590-TRIAL/changes"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2016-15059"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-74766"
  ]
}

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.

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.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

CVE-2026-74766 (GCVE-0-2026-74766)

FKIE_CVE-2026-74766

GHSA-QFFM-J59F-77QW

UBUNTU-CVE-2026-74766 (CVE-2026-74766)

Tags

Sightings

Nomenclature

Related by attack behaviour