High

Quadratic fragment-name uniqueness check causes denial of service in absinthe

Type: advisorySources: OSV

Inefficient Algorithmic Complexity vulnerability in absinthe-graphql absinthe allows unauthenticated denial of service via quadratic fragment-name uniqueness validation. 'Elixir.Absinthe.Phase.Document.Validation.UniqueFragmentNames':run/2 iterates over all fragments and for each one calls duplicate?/2, which evaluates Enum.count(fragments, &(&1.name == name)) — a full linear scan of the fragment list. The result is O(N²) comparisons per document, where N is the number of fragment definitions supplied by the caller. Because input.fragments is built directly from the GraphQL query body, N is fully attacker-controlled. A minimum-size fragment definition is roughly 16 bytes, so a ~1 MB document carries ~60,000 fragments and forces ~3.6 × 10⁹ comparisons inside this single validation phase. No authentication, schema knowledge, or special configuration is required. This issue affects absinthe: from 1.2.0 before 1.10.2.

Products: Not specified
Affected versions: Not specified
Fixed versions: Not specified
CVEs: CVE-2026-43967
Confirmed fixed CVEs: Not specified
Updated in this feed: 3 Nov 2026, 02:41 UTC · Revision 1

Source evidence

Quadratic fragment-name uniqueness check causes denial of service in absinthe

core-osv · Original source

Published 8 May 2026, 15:42 UTC

osv:CVE-2026-43967

Complete source record

{
  "id": "8d64d40851622df432239b663354fce7514f894abc1a430090ffcf8e54360d83",
  "url": "https://osv.dev/vulnerability/CVE-2026-43967",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Quadratic fragment-name uniqueness check causes denial of service in absinthe",
    "summary": "Inefficient Algorithmic Complexity vulnerability in absinthe-graphql absinthe allows unauthenticated denial of service via quadratic fragment-name uniqueness validation. 'Elixir.Absinthe.Phase.Document.Validation.UniqueFragmentNames':run/2 iterates over all fragments and for each one calls duplicate?/2, which evaluates Enum.count(fragments, &(&1.name == name)) — a full linear scan of the fragment list. The result is O(N²) comparisons per document, where N is the number of fragment definitions supplied by the caller. Because input.fragments is built directly from the GraphQL query body, N is fully attacker-controlled. A minimum-size fragment definition is roughly 16 bytes, so a ~1 MB document carries ~60,000 fragments and forces ~3.6 × 10⁹ comparisons inside this single validation phase. No authentication, schema knowledge, or special configuration is required. This issue affects absinthe: from 1.2.0 before 1.10.2.",
    "evidence": "osv:CVE-2026-43967",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-43967",
      "aliases": [
        "CVE-2026-43967",
        "EEF-CVE-2026-43967",
        "GHSA-9mhv-8h52-q7q2"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/absinthe-graphql/absinthe",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0b46e3bcc06c0d3797bacd64761b908a84646c1d"
                },
                {
                  "fixed": "223600c520493dcaf95080af552c413099f92c9d"
                },
                {
                  "introduced": "26e7619e83e0612ff4922d940627d51ab7c07e45"
                },
                {
                  "fixed": "c0c265cacc7f8ed5025b0bfa22f6f5e00145e919"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0b46e3bcc06c0d3797bacd64761b908a84646c1d"
                      },
                      {
                        "fixed": "223600c520493dcaf95080af552c413099f92c9d"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "range": [
                      {
                        "introduced": "1.2.0"
                      },
                      {
                        "fixed": "1.10.2"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "range": [
                      {
                        "fixed": "223600c520493dcaf95080af552c413099f92c9d"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v1.10.1",
            "v1.10.0",
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            "v1.8.0",
            "v1.7.11",
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            "v1.5.0",
            "v1.5.0-rc.5",
            "v1.5.0-rc.4",
            "v1.5.0-rc.3",
            "v1.5.0-rc.2",
            "v1.5.0-rc.1",
            "v1.5.0-rc.0",
            "v1.5.0-beta.2",
            "v1.5.0-alpha.4",
            "v1.5.0-alpha.2",
            "v1.4.10",
            "v1.4.7",
            "v1.4.6",
            "v1.4.5",
            "v1.4.4",
            "v1.4.3",
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          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-43967.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:25.124912820Z",
      "provider": "osv",
      "references": [
        "https://cna.erlef.org/cves/CVE-2026-43967.html",
        "https://github.com",
        "https://osv.dev/vulnerability/EEF-CVE-2026-43967",
        "https://repo.hex.pm",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/43xxx/CVE-2026-43967.json",
        "https://github.com/absinthe-graphql/absinthe/security/advisories/GHSA-9mhv-8h52-q7q2",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-43967",
        "https://github.com/absinthe-graphql/absinthe/commit/223600c520493dcaf95080af552c413099f92c9d",
        "https://github.com/absinthe-graphql/absinthe"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-407"
        ],
        "cna_assigner": "EEF",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/43xxx/CVE-2026-43967.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-43967",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 491960,
  "published_at": "2026-05-08T15:42:34.347+00:00"
}