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GHSA-43F3-46VJ-X5JC

Vulnerability from github – Published: 2026-10-06 21:31 – Updated: 2026-10-06 21:31

Details

Inefficient Regular Expression Complexity (CWE-1333) in Elasticsearch can lead to denial of service via Regular Expression Exponential Blowup (CAPEC-492). The ES|QL CHUNK function's recursive chunking strategy accepts a list of user-supplied regular expressions used as text-splitting separators, without validating their computational complexity or bounding their execution time. An authenticated user with read access to any text-based index can submit a specially crafted regular expression that triggers catastrophic backtracking, consuming excessive CPU on Elasticsearch worker threads and degrading query throughput for other tenants on the affected node. The cluster does not crash as a result of this issue.

Severity

4.3 (Medium)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-102408"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-1333"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-06T20:17:12Z",
    "severity": "MODERATE"
  },
  "details": "Inefficient Regular Expression Complexity (CWE-1333) in Elasticsearch can lead to denial of service via Regular Expression Exponential Blowup (CAPEC-492). The ES|QL CHUNK function\u0027s recursive chunking strategy accepts a list of user-supplied regular expressions used as text-splitting separators, without validating their computational complexity or bounding their execution time. An authenticated user with read access to any text-based index can submit a specially crafted regular expression that triggers catastrophic backtracking, consuming excessive CPU on Elasticsearch worker threads and degrading query throughput for other tenants on the affected node. The cluster does not crash as a result of this issue.",
  "id": "GHSA-43f3-46vj-x5jc",
  "modified": "2026-10-06T21:31:55Z",
  "published": "2026-10-06T21:31:55Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-102408"
    },
    {
      "type": "WEB",
      "url": "https://discuss.elastic.co/t/elasticsearch-8-19-22-9-4-8-and-9-5-5-security-update-esa-2026-189/390862"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-102408 (GCVE-0-2026-102408)

Vulnerability from cvelistv5 – Published: 2026-10-06 19:31 – Updated: 2026-10-06 19:56

Title

Inefficient Regular Expression Complexity in Elasticsearch Leading to Denial of Service

Summary

Severity

4.3 (Medium)


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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-10-06 19:55 UTC

CWE

CWE-1333 - Inefficient Regular Expression Complexity

Assigner

elastic mitre root Scorecard

References

1 reference

URL	Tags
https://discuss.elastic.co/t/elasticsearch-8-19-2…

Impacted products

1 product

Vendor	Product	Version
Elastic	Elasticsearch	Affected: 8.19.0 , ≤ 8.19.21 (semver) Affected: 9.1.0 , ≤ 9.3.8 (semver) Affected: 9.4.0 , ≤ 9.4.7 (semver) Affected: 9.5.0 , ≤ 9.5.4 (semver)

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-102408",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-10-06T19:55:55.653697Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-10-06T19:56:06.441Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
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          "product": "Elasticsearch",
          "vendor": "Elastic",
          "versions": [
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              "lessThanOrEqual": "8.19.21",
              "status": "affected",
              "version": "8.19.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "9.3.8",
              "status": "affected",
              "version": "9.1.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "9.4.7",
              "status": "affected",
              "version": "9.4.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "9.5.4",
              "status": "affected",
              "version": "9.5.0",
              "versionType": "semver"
            }
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        }
      ],
      "descriptions": [
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            }
          ],
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          "capecId": "CAPEC-492",
          "descriptions": [
            {
              "lang": "en",
              "value": "CAPEC-492 Regular Expression Exponential Blowup"
            }
          ]
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "LOW",
            "baseScore": 4.3,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
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          "scenarios": [
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        "orgId": "271b6943-45a9-4f3a-ab4e-976f3fa05b5a",
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      "references": [
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          "url": "https://discuss.elastic.co/t/elasticsearch-8-19-22-9-4-8-and-9-5-5-security-update-esa-2026-189/390862"
        }
      ],
      "source": {
        "discovery": "Elastic"
      },
      "title": "Inefficient Regular Expression Complexity in Elasticsearch Leading to Denial of Service",
      "x_generator": {
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    "datePublished": "2026-10-06T19:31:39.196Z",
    "dateReserved": "2026-09-29T02:06:02.426Z",
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    "state": "PUBLISHED"
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}

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.

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GHSA-43F3-46VJ-X5JC

CVE-2026-102408 (GCVE-0-2026-102408)

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