Vulnerability-Lookup

GHSA-2CXW-QMFC-3VX3

Vulnerability from github – Published: 2026-08-09 18:30 – Updated: 2026-08-10 00:31

Details

Perl versions through 5.45.1 have out-of-bounds heap reads and writes during regular expression matching via an undersized superlinear cache in S_regmatch.

The regex engine's superlinear cache holds one bit per subject position for each participating WHILEM node, so the bit count is the subject length plus one times the number of nodes. Nothing checks that product for positive overflow of the signed 32-bit count: a 286331153 byte subject matched against a pattern with 15 participating nodes stores the count as 14, leaving a two byte cache. The cache is then indexed from the real match position and node number, so reads go past the end of the allocation, and on failure CACHEsayNO sets a bit past it.

A caller that matches an attacker controlled subject of this size against a pattern of this shape can crash the process or corrupt heap memory.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-15534"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-125"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-09T18:16:42Z",
    "severity": null
  },
  "details": "Perl versions through 5.45.1 have out-of-bounds heap reads and writes during regular expression matching via an undersized superlinear cache in S_regmatch.\n\nThe regex engine\u0027s superlinear cache holds one bit per subject position for each participating WHILEM node, so the bit count is the subject length plus one times the number of nodes. Nothing checks that product for positive overflow of the signed 32-bit count: a 286331153 byte subject matched against a pattern with 15 participating nodes stores the count as 14, leaving a two byte cache. The cache is then indexed from the real match position and node number, so reads go past the end of the allocation, and on failure CACHEsayNO sets a bit past it.\n\nA caller that matches an attacker controlled subject of this size against a pattern of this shape can crash the process or corrupt heap memory.",
  "id": "GHSA-2cxw-qmfc-3vx3",
  "modified": "2026-08-10T00:31:42Z",
  "published": "2026-08-09T18:30:26Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-15534"
    },
    {
      "type": "WEB",
      "url": "https://github.com/Perl/perl5/commit/54cf3d44cbbedd17d774e9a37921963e8fd5d0cb.patch"
    },
    {
      "type": "WEB",
      "url": "https://github.com/Perl/perl5/commit/568e6fd238867bb9e99fa3f47cba3169009239e0.patch"
    },
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2026/08/09/12"
    },
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2026/08/09/13"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-15534 (GCVE-0-2026-15534)

Vulnerability from cvelistv5 – Published: 2026-08-09 17:49 – Updated: 2026-08-09 22:07

Title

Perl versions through 5.45.1 have out-of-bounds heap reads and writes during regular expression matching via an undersized superlinear cache in S_regmatch

Summary

Perl versions through 5.45.1 have out-of-bounds heap reads and writes during regular expression matching via an undersized superlinear cache in S_regmatch. The regex engine's superlinear cache holds one bit per subject position for each participating WHILEM node, so the bit count is the subject length plus one times the number of nodes. Nothing checks that product for positive overflow of the signed 32-bit count: a 286331153 byte subject matched against a pattern with 15 participating nodes stores the count as 14, leaving a two byte cache. The cache is then indexed from the real match position and node number, so reads go past the end of the allocation, and on failure CACHEsayNO sets a bit past it. A caller that matches an attacker controlled subject of this size against a pattern of this shape can crash the process or corrupt heap memory.

Severity

No CVSS data available.

CWE

CWE-190 - Integer Overflow or Wraparound
CWE-125 - Out-of-bounds Read
CWE-787 - Out-of-bounds Write

Assigner

CPANSec

References

4 references

URL	Tags
https://github.com/Perl/perl5/commit/568e6fd23886…	patch
https://github.com/Perl/perl5/commit/54cf3d44cbbe…	patch
http://www.openwall.com/lists/oss-security/2026/0…
http://www.openwall.com/lists/oss-security/2026/0…

Impacted products

1 product

Vendor	Product	Version
LEONT	perl	Affected: 0 , ≤ 5.45.1 (custom)

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JSON

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        "providerMetadata": {
          "dateUpdated": "2026-08-09T22:07:56.263Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
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          {
            "url": "http://www.openwall.com/lists/oss-security/2026/08/09/12"
          },
          {
            "url": "http://www.openwall.com/lists/oss-security/2026/08/09/13"
          }
        ],
        "title": "CVE Program Container"
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    ],
    "cna": {
      "affected": [
        {
          "collectionURL": "https://cpan.org/modules",
          "defaultStatus": "unaffected",
          "packageName": "perl",
          "product": "perl",
          "programFiles": [
            "regexec.c"
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          "programRoutines": [
            {
              "name": "S_regmatch"
            }
          ],
          "repo": "https://github.com/Perl/perl5",
          "vendor": "LEONT",
          "versions": [
            {
              "lessThanOrEqual": "5.45.1",
              "status": "affected",
              "version": "0",
              "versionType": "custom"
            }
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        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Perl versions through 5.45.1 have out-of-bounds heap reads and writes during regular expression matching via an undersized superlinear cache in S_regmatch.\n\nThe regex engine\u0027s superlinear cache holds one bit per subject position for each participating WHILEM node, so the bit count is the subject length plus one times the number of nodes. Nothing checks that product for positive overflow of the signed 32-bit count: a 286331153 byte subject matched against a pattern with 15 participating nodes stores the count as 14, leaving a two byte cache. The cache is then indexed from the real match position and node number, so reads go past the end of the allocation, and on failure CACHEsayNO sets a bit past it.\n\nA caller that matches an attacker controlled subject of this size against a pattern of this shape can crash the process or corrupt heap memory."
        }
      ],
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        {
          "descriptions": [
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              "type": "CWE"
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        },
        {
          "descriptions": [
            {
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              "description": "CWE-125 Out-of-bounds Read",
              "lang": "en",
              "type": "CWE"
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          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-787",
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      "providerMetadata": {
        "dateUpdated": "2026-08-09T17:49:50.033Z",
        "orgId": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
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      "references": [
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          "url": "https://github.com/Perl/perl5/commit/568e6fd238867bb9e99fa3f47cba3169009239e0.patch"
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          "url": "https://github.com/Perl/perl5/commit/54cf3d44cbbedd17d774e9a37921963e8fd5d0cb.patch"
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      ],
      "solutions": [
        {
          "lang": "en",
          "value": "Upgrade to a future Perl release, or apply the upstream patches."
        }
      ],
      "source": {
        "discovery": "UNKNOWN"
      },
      "title": "Perl versions through 5.45.1 have out-of-bounds heap reads and writes during regular expression matching via an undersized superlinear cache in S_regmatch",
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  "cveMetadata": {
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    "assignerShortName": "CPANSec",
    "cveId": "CVE-2026-15534",
    "datePublished": "2026-08-09T17:49:50.033Z",
    "dateReserved": "2026-07-12T17:04:25.249Z",
    "dateUpdated": "2026-08-09T22:07:56.263Z",
    "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.

Detection rules are retrieved from Rulezet.

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.

Action not permitted

GHSA-2CXW-QMFC-3VX3

CVE-2026-15534 (GCVE-0-2026-15534)

Tags

Sightings

Nomenclature