Vulnerability-Lookup

UBUNTU-CVE-2026-5089 (CVE-2026-5089)

Vulnerability from osv_ubuntu – Published: 2026-05-12 17:16 – Updated: 2026-05-20 21:45 – Source website

Details

YAML::Syck versions before 1.38 for Perl has an out-of-bounds read. The base60 (sexagesimal) parsing code in perl_syck.h has a buffer underflow bug in both int#base60 and float#base60 handlers. When processing the leftmost segment of a colon-separated value (e.g., the 1 in 1:30:45), the inner while loop can decrement a pointer past the start of the string buffer: while ( colon >= ptr && colon != ':' ) { colon--; } if ( colon == ':' ) colon = '\0'; // colon may be ptr-1 here When no colon is found (final/leftmost segment), colon becomes ptr-1, and the subsequent colon dereference reads one byte before the allocated buffer.

Severity

7.3 (High)


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

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-5089	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-5089	REPORT
	https://lists.security.metacpan.org/cve-announce/…	REPORT
	https://github.com/cpan-authors/YAML-Syck/issues/132	REPORT
	https://github.com/cpan-authors/YAML-Syck/pull/133	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libyaml-syck-perl",
            "binary_version": "1.29-1ubuntu0.16.04.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:16.04:LTS",
        "name": "libyaml-syck-perl",
        "purl": "pkg:deb/ubuntu/libyaml-syck-perl@1.29-1ubuntu0.16.04.1~esm1?arch=source\u0026distro=esm-apps/xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.27-2build2",
        "1.29-1",
        "1.29-1build1",
        "1.29-1ubuntu0.16.04.1~esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libyaml-syck-perl",
            "binary_version": "1.29-1ubuntu0.18.04.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:18.04:LTS",
        "name": "libyaml-syck-perl",
        "purl": "pkg:deb/ubuntu/libyaml-syck-perl@1.29-1ubuntu0.18.04.1~esm1?arch=source\u0026distro=esm-apps/bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.29-1build3",
        "1.29-1ubuntu0.18.04.1~esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libyaml-syck-perl",
            "binary_version": "1.31-1ubuntu0.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:20.04:LTS",
        "name": "libyaml-syck-perl",
        "purl": "pkg:deb/ubuntu/libyaml-syck-perl@1.31-1ubuntu0.1~esm1?arch=source\u0026distro=esm-apps/focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.31-1",
        "1.31-1build1",
        "1.31-1ubuntu0.1~esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libyaml-syck-perl",
            "binary_version": "1.34-1ubuntu0.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:22.04:LTS",
        "name": "libyaml-syck-perl",
        "purl": "pkg:deb/ubuntu/libyaml-syck-perl@1.34-1ubuntu0.1~esm1?arch=source\u0026distro=esm-apps/jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.34-1build1",
        "1.34-1build2",
        "1.34-1ubuntu0.1~esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libyaml-syck-perl",
            "binary_version": "1.34-2ubuntu0.24.04.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:24.04:LTS",
        "name": "libyaml-syck-perl",
        "purl": "pkg:deb/ubuntu/libyaml-syck-perl@1.34-2ubuntu0.24.04.1~esm1?arch=source\u0026distro=esm-apps/noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.34-2",
        "1.34-2build1",
        "1.34-2build2",
        "1.34-2build3",
        "1.34-2ubuntu0.24.04.1~esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libyaml-syck-perl",
            "binary_version": "1.34-3ubuntu0.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:25.10",
        "name": "libyaml-syck-perl",
        "purl": "pkg:deb/ubuntu/libyaml-syck-perl@1.34-3ubuntu0.1?arch=source\u0026distro=questing"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.34-2build4",
        "1.34-3",
        "1.34-3ubuntu0.1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libyaml-syck-perl",
            "binary_version": "1.36-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "libyaml-syck-perl",
        "purl": "pkg:deb/ubuntu/libyaml-syck-perl@1.36-1?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.34-3",
        "1.34-4",
        "1.36-1"
      ]
    }
  ],
  "aliases": [],
  "details": "YAML::Syck versions before 1.38 for Perl  has an out-of-bounds read. The base60 (sexagesimal) parsing code in perl_syck.h has a buffer underflow bug in both int#base60 and float#base60 handlers. When processing the leftmost segment of a colon-separated value (e.g., the 1 in 1:30:45), the inner while loop can decrement a pointer past the start of the string buffer:     while ( colon \u003e= ptr \u0026\u0026 *colon != \u0027:\u0027 )     {         colon--;     }     if ( *colon == \u0027:\u0027 ) *colon = \u0027\\0\u0027;  // colon may be ptr-1 here When no colon is found (final/leftmost segment), colon becomes ptr-1, and the subsequent *colon dereference reads one byte before the allocated buffer.",
  "id": "UBUNTU-CVE-2026-5089",
  "modified": "2026-05-20T21:45:04Z",
  "published": "2026-05-12T17:16:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-5089"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-5089"
    },
    {
      "type": "REPORT",
      "url": "https://lists.security.metacpan.org/cve-announce/msg/39981051/"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/cpan-authors/YAML-Syck/issues/132"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/cpan-authors/YAML-Syck/pull/133"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-5089"
  ]
}

CVE-2026-5089 (GCVE-0-2026-5089)

Vulnerability from cvelistv5 – Published: 2026-05-12 16:14 – Updated: 2026-05-14 13:51

Title

YAML::Syck versions before 1.38 for Perl has an out-of-bounds read

Summary

YAML::Syck versions before 1.38 for Perl has an out-of-bounds read. The base60 (sexagesimal) parsing code in perl_syck.h has a buffer underflow bug in both int#base60 and float#base60 handlers. When processing the leftmost segment of a colon-separated value (e.g., the 1 in 1:30:45), the inner while loop can decrement a pointer past the start of the string buffer: while ( colon >= ptr && *colon != ':' ) { colon--; } if ( *colon == ':' ) *colon = '\0'; // colon may be ptr-1 here When no colon is found (final/leftmost segment), colon becomes ptr-1, and the subsequent *colon dereference reads one byte before the allocated buffer.

Severity

7.3 (High)


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

SSVC

Exploitation: poc Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-05-14 13:50 UTC

CWE

CWE-124 - Buffer Underwrite ('Buffer Underflow')

Assigner

CPANSec redhat root

References

5 references

URL	Tags
https://metacpan.org/release/TODDR/YAML-Syck-1.38…	release-notes
https://github.com/cpan-authors/YAML-Syck/issues/132	issue-tracking
https://github.com/cpan-authors/YAML-Syck/pull/133	issue-tracking
https://github.com/cpan-authors/YAML-Syck/commit/…	patch
http://www.openwall.com/lists/oss-security/2026/0…

Impacted products

1 product

Vendor	Product	Version
TODDR	YAML::Syck	Affected: 0 , < 1.38 (custom)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "providerMetadata": {
          "dateUpdated": "2026-05-12T18:35:46.042Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "url": "http://www.openwall.com/lists/oss-security/2026/05/12/16"
          }
        ],
        "title": "CVE Program Container"
      },
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "NETWORK",
              "availabilityImpact": "LOW",
              "baseScore": 7.3,
              "baseSeverity": "HIGH",
              "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:L",
              "version": "3.1"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2026-5089",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-05-14T13:50:53.123874Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-05-14T13:51:01.952Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "references": [
          {
            "tags": [
              "exploit"
            ],
            "url": "https://github.com/cpan-authors/YAML-Syck/issues/132"
          }
        ],
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "collectionURL": "https://cpan.org/modules",
          "defaultStatus": "unaffected",
          "packageName": "YAML-Syck",
          "product": "YAML::Syck",
          "programFiles": [
            "perl_syck.h"
          ],
          "repo": "https://github.com/toddr/YAML-Syck",
          "vendor": "TODDR",
          "versions": [
            {
              "lessThan": "1.38",
              "status": "affected",
              "version": "0",
              "versionType": "custom"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "YAML::Syck versions before 1.38 for Perl  has an out-of-bounds read.\n\nThe base60 (sexagesimal) parsing code in perl_syck.h has a buffer underflow bug in both int#base60 and float#base60 handlers. When processing the leftmost segment of a colon-separated value (e.g., the 1 in 1:30:45), the inner while loop can decrement a pointer past the start of the string buffer:\n\n    while ( colon \u003e= ptr \u0026\u0026 *colon != \u0027:\u0027 )\n    {\n        colon--;\n    }\n    if ( *colon == \u0027:\u0027 ) *colon = \u0027\\0\u0027;  // colon may be ptr-1 here\n\nWhen no colon is found (final/leftmost segment), colon becomes ptr-1, and the subsequent *colon dereference reads one byte before the allocated buffer."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-124",
              "description": "CWE-124 Buffer Underwrite (\u0027Buffer Underflow\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-12T16:14:21.951Z",
        "orgId": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
        "shortName": "CPANSec"
      },
      "references": [
        {
          "tags": [
            "release-notes"
          ],
          "url": "https://metacpan.org/release/TODDR/YAML-Syck-1.38/changes"
        },
        {
          "tags": [
            "issue-tracking"
          ],
          "url": "https://github.com/cpan-authors/YAML-Syck/issues/132"
        },
        {
          "tags": [
            "issue-tracking"
          ],
          "url": "https://github.com/cpan-authors/YAML-Syck/pull/133"
        },
        {
          "tags": [
            "patch"
          ],
          "url": "https://github.com/cpan-authors/YAML-Syck/commit/208a4d3bd1b5cdb4a791a6e3905bd6bd45e9d005.patch"
        }
      ],
      "solutions": [
        {
          "lang": "en",
          "value": "Upgrade to YAML::Syck version 1.38 or later."
        }
      ],
      "source": {
        "discovery": "UNKNOWN"
      },
      "title": "YAML::Syck versions before 1.38 for Perl has an out-of-bounds read",
      "x_generator": {
        "engine": "cpansec-cna-tool 0.1"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
    "assignerShortName": "CPANSec",
    "cveId": "CVE-2026-5089",
    "datePublished": "2026-05-12T16:14:21.951Z",
    "dateReserved": "2026-03-28T19:33:37.653Z",
    "dateUpdated": "2026-05-14T13:51:01.952Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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

UBUNTU-CVE-2026-5089 (CVE-2026-5089)

CVE-2026-5089 (GCVE-0-2026-5089)

Tags

Sightings

Nomenclature

Related by attack behaviour