{"id":"CVE-2026-108357","state":"PUBLISHED","title":"PhpSpreadsheet: XmlScanner Bypass via Double-Encoded unentity() TOCTOU Allows XXE and Denial of Service","description":"PhpSpreadsheet is a pure PHP library for reading and writing spreadsheet files. From 3.3.0 until 3.10.8 and 5.10.0, Reader\\Xml passes stored SpreadsheetML XML through XmlScanner::scan in Xml::canRead and Xml::trySimpleXMLLoadStringPrivate, while Xml::unentity decodes numeric entities only after each DOCTYPE pattern check. A double-encoded less-than character is reduced by the first callback to another encoded character and by the second callback to a literal less-than sign, so SimpleXML receives an unchecked DOCTYPE and entity declaration. Processing attacker-controlled SpreadsheetML XML can cause entity-expansion denial of service and can permit local file access or SSRF on PHP before 8.0 or when LIBXML_NOENT is enabled. This issue is fixed in versions 3.10.8 and 5.10.0.","publishedAt":"2026-10-22T17:38:16.098Z","updatedAt":"2026-10-23T21:08:17.784Z","severity":{"score":8.8,"label":"High","version":"4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:H/SC:L/SI:N/SA:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["PHPOffice PhpSpreadsheet"],"affected":[{"vendor":"PHPOffice","product":"PhpSpreadsheet","versions":[{"version":">= 3.3.0, < 3.10.8","status":"affected"},{"version":">= 4.0.0, < 5.10.0","status":"affected"}]}],"references":["https://github.com/PHPOffice/PhpSpreadsheet/security/advisories/GHSA-rxj4-h86g-25gc","https://github.com/PHPOffice/PhpSpreadsheet/commit/89f455c133e1a7e2d4abfadc43ce29eb7450d781","https://github.com/PHPOffice/PhpSpreadsheet/commit/980b5c294493856f1a25754f1e8a1d2185b93738","https://github.com/PHPOffice/PhpSpreadsheet/releases/tag/3.10.8","https://github.com/PHPOffice/PhpSpreadsheet/releases/tag/5.10.0"],"weaknesses":["CWE-611","CWE-776"],"ingestedAt":"2026-10-29T20:10:33.477Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/108xxx/CVE-2026-108357.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-108357","state":"PUBLISHED","datePublished":"2026-10-22T17:38:16.098Z","dateUpdated":"2026-10-23T21:08:17.784Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-10-09T20:32:44.301Z"},"containers":{"cna":{"title":"PhpSpreadsheet: XmlScanner Bypass via Double-Encoded unentity() TOCTOU Allows XXE and Denial of Service","descriptions":[{"lang":"en","value":"PhpSpreadsheet is a pure PHP library for reading and writing spreadsheet files. From 3.3.0 until 3.10.8 and 5.10.0, Reader\\Xml passes stored SpreadsheetML XML through XmlScanner::scan in Xml::canRead and Xml::trySimpleXMLLoadStringPrivate, while Xml::unentity decodes numeric entities only after each DOCTYPE pattern check. A double-encoded less-than character is reduced by the first callback to another encoded character and by the second callback to a literal less-than sign, so SimpleXML receives an unchecked DOCTYPE and entity declaration. Processing attacker-controlled SpreadsheetML XML can cause entity-expansion denial of service and can permit local file access or SSRF on PHP before 8.0 or when LIBXML_NOENT is enabled. This issue is fixed in versions 3.10.8 and 5.10.0."}],"affected":[{"vendor":"PHPOffice","product":"PhpSpreadsheet","versions":[{"version":">= 3.3.0, < 3.10.8","status":"affected"},{"version":">= 4.0.0, < 5.10.0","status":"affected"}]}],"references":[{"url":"https://github.com/PHPOffice/PhpSpreadsheet/security/advisories/GHSA-rxj4-h86g-25gc","name":"https://github.com/PHPOffice/PhpSpreadsheet/security/advisories/GHSA-rxj4-h86g-25gc","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/PHPOffice/PhpSpreadsheet/commit/89f455c133e1a7e2d4abfadc43ce29eb7450d781","name":"https://github.com/PHPOffice/PhpSpreadsheet/commit/89f455c133e1a7e2d4abfadc43ce29eb7450d781","tags":["x_refsource_MISC"]},{"url":"https://github.com/PHPOffice/PhpSpreadsheet/commit/980b5c294493856f1a25754f1e8a1d2185b93738","name":"https://github.com/PHPOffice/PhpSpreadsheet/commit/980b5c294493856f1a25754f1e8a1d2185b93738","tags":["x_refsource_MISC"]},{"url":"https://github.com/PHPOffice/PhpSpreadsheet/releases/tag/3.10.8","name":"https://github.com/PHPOffice/PhpSpreadsheet/releases/tag/3.10.8","tags":["x_refsource_MISC"]},{"url":"https://github.com/PHPOffice/PhpSpreadsheet/releases/tag/5.10.0","name":"https://github.com/PHPOffice/PhpSpreadsheet/releases/tag/5.10.0","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"LOW","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"HIGH","subConfidentialityImpact":"LOW","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":8.8,"baseSeverity":"HIGH","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:H/SC:L/SI:N/SA:N","version":"4.0"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-611","lang":"en","description":"CWE-611: Improper Restriction of XML External Entity Reference","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-776","lang":"en","description":"CWE-776: Improper Restriction of Recursive Entity References in DTDs ('XML Entity Expansion')","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-10-22T17:38:16.098Z"},"source":{"advisory":"GHSA-rxj4-h86g-25gc","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-10-23T17:32:57.479788Z","id":"CVE-2026-108357","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-23T21:08:17.784Z"}}]}}}