pypdf: Possible infinite loop when removing tree items

{
  "id": "c266269e8c2a4f52657f2a98352836b2f02f8c7bfe5c99c8fb507eb48179e4be",
  "url": "https://www.cve.org/CVERecord?id=CVE-2026-113793",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "pypdf: Possible infinite loop when removing tree items",
    "summary": "pypdf is a free and open-source pure-python PDF library. Prior to 6.20.1, removing an object from a crafted cyclic PDF tree, such as an outline item, can enter an infinite loop and block the current process. This issue is fixed in version 6.20.1.",
    "evidence": "cve:CVE-2026-113793",
    "products": [
      {
        "name": {
          "value": "pypdf",
          "evidence": "/containers/cna/affected/0/product"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": []
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-113793",
      "aliases": [
        "CVE-2026-113793"
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "version": "4.0",
            "baseScore": 6,
            "attackVector": "NETWORK",
            "baseSeverity": "MEDIUM",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
            "userInteraction": "PASSIVE",
            "attackComplexity": "LOW",
            "attackRequirements": "PRESENT",
            "privilegesRequired": "NONE",
            "subIntegrityImpact": "NONE",
            "vulnIntegrityImpact": "NONE",
            "subAvailabilityImpact": "NONE",
            "vulnAvailabilityImpact": "HIGH",
            "subConfidentialityImpact": "NONE",
            "vulnConfidentialityImpact": "NONE"
          }
        }
      ],
      "affected": [
        {
          "vendor": "py-pdf",
          "product": "pypdf",
          "versions": [
            {
              "status": "affected",
              "version": "< 6.20.1"
            }
          ]
        }
      ],
      "modified": "2026-10-28T17:01:30.870Z",
      "provider": "cve",
      "references": [
        "https://github.com/py-pdf/pypdf/security/advisories/GHSA-9mx8-4j7g-633p",
        "https://github.com/py-pdf/pypdf/pull/4188",
        "https://github.com/py-pdf/pypdf/commit/c9c35b4471c2eb5fe078094f6c816e69d4ed25a0",
        "https://github.com/py-pdf/pypdf/releases/tag/6.20.1"
      ],
      "provider_metadata": {
        "adp": [
          {
            "title": "CISA ADP Vulnrichment",
            "metrics": [
              {
                "other": {
                  "type": "ssvc",
                  "content": {
                    "id": "CVE-2026-113793",
                    "role": "CISA Coordinator",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "no"
                      },
                      {
                        "Technical Impact": "partial"
                      }
                    ],
                    "version": "2.0.3",
                    "timestamp": "2026-10-28T16:51:43.110456Z"
                  }
                }
              }
            ],
            "providerMetadata": {
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP",
              "dateUpdated": "2026-10-28T17:01:30.870Z"
            }
          }
        ],
        "cna": {
          "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
          "shortName": "GitHub_M",
          "dateUpdated": "2026-10-21T15:57:55.600Z"
        }
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-113793",
        "evidence": "/cveMetadata/cveId"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/containers/cna/metrics"
  },
  "source_id": "core-cve",
  "document_id": 462545,
  "published_at": "2026-10-21T15:57:55.6+00:00"
}