CVE-2026-5089 (GCVE-0-2026-5089)
Vulnerability from cvelistv5
Published
2026-05-12 16:14
Modified
2026-05-14 13:51
CWE
  • CWE-124 - Buffer Underwrite ('Buffer Underflow')
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.
Impacted products
Vendor Product Version
TODDR YAML::Syck Version: 0   < 1.38
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Show details on NVD website


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        "providerMetadata": {
          "dateUpdated": "2026-05-12T18:35:46.042Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
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        "references": [
          {
            "url": "http://www.openwall.com/lists/oss-security/2026/05/12/16"
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        "title": "CVE Program Container"
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        "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"
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              "content": {
                "id": "CVE-2026-5089",
                "options": [
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                  {
                    "Technical Impact": "partial"
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                "role": "CISA Coordinator",
                "timestamp": "2026-05-14T13:50:53.123874Z",
                "version": "2.0.3"
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        "providerMetadata": {
          "dateUpdated": "2026-05-14T13:51:01.952Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
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            "tags": [
              "exploit"
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            "url": "https://github.com/cpan-authors/YAML-Syck/issues/132"
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        "title": "CISA ADP Vulnrichment"
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    "cna": {
      "affected": [
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          "collectionURL": "https://cpan.org/modules",
          "defaultStatus": "unaffected",
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          "product": "YAML::Syck",
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          "vendor": "TODDR",
          "versions": [
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              "version": "0",
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          "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."
        }
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      "problemTypes": [
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          "descriptions": [
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        "orgId": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
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      "references": [
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          "tags": [
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          "url": "https://metacpan.org/release/TODDR/YAML-Syck-1.38/changes"
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          "tags": [
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          "url": "https://github.com/cpan-authors/YAML-Syck/issues/132"
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          "url": "https://github.com/cpan-authors/YAML-Syck/pull/133"
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        }
      ],
      "solutions": [
        {
          "lang": "en",
          "value": "Upgrade to YAML::Syck version 1.38 or later."
        }
      ],
      "source": {
        "discovery": "UNKNOWN"
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      "title": "YAML::Syck versions before 1.38 for Perl has an out-of-bounds read",
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    "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"
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  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
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