{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-52767", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "state": "PUBLISHED", "assignerShortName": "GitHub_M", "dateReserved": "2026-06-08T17:13:43.064Z", "datePublished": "2026-09-04T23:40:39.725Z", "dateUpdated": "2026-09-04T23:40:39.725Z"}, "containers": {"cna": {"title": "YesWiki: Unauthenticated ActivityPub Signature-Verification Bypass via `!openssl_verify(...)` accepting `int(-1)`", "problemTypes": [{"descriptions": [{"cweId": "CWE-347", "lang": "en", "description": "CWE-347: Improper Verification of Cryptographic Signature", "type": "CWE"}]}], "metrics": [{"cvssV3_1": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "LOW", "baseScore": 8.2, "baseSeverity": "HIGH", "confidentialityImpact": "NONE", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L", "version": "3.1"}}], "references": [{"name": "https://github.com/YesWiki/yeswiki/security/advisories/GHSA-mv28-wj57-f57g", "tags": ["x_refsource_CONFIRM"], "url": "https://github.com/YesWiki/yeswiki/security/advisories/GHSA-mv28-wj57-f57g"}, {"name": "https://github.com/YesWiki/yeswiki/commit/d1795e0301e1a1078f17b4b98f56fff70de2029e", "tags": ["x_refsource_MISC"], "url": "https://github.com/YesWiki/yeswiki/commit/d1795e0301e1a1078f17b4b98f56fff70de2029e"}, {"name": "https://github.com/YesWiki/yeswiki/releases/tag/v4.6.6", "tags": ["x_refsource_MISC"], "url": "https://github.com/YesWiki/yeswiki/releases/tag/v4.6.6"}], "affected": [{"vendor": "YesWiki", "product": "yeswiki", "versions": [{"version": ">= 4.6.2, < 4.6.6", "status": "affected"}]}], "providerMetadata": {"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M", "dateUpdated": "2026-09-04T23:40:39.725Z"}, "descriptions": [{"lang": "en", "value": "YesWiki is a wiki system written in PHP. From version 4.6.2 to before version 4.6.6, HttpSignatureService::verifySignature() checks the result of PHP's openssl_verify() with a loose boolean negation - if (!openssl_verify(...)) { throw ... }. PHP's openssl_verify has four possible return values: 1, 0, -1, and \"false\". The -1 row is the bypass: PHP's truthiness rules make -1 a truthy value, so !(-1) === false, the throw is skipped, and the controller proceeds to processActivity(). Any condition that makes OpenSSL's EVP_VerifyFinal() return -1 triggers the bypass. The reachable consequence is the controller silently treats a failed verification as success and processes the attacker's payload. This issue has been patched in version 4.6.6."}], "source": {"advisory": "GHSA-mv28-wj57-f57g", "discovery": "UNKNOWN"}}}}

{}

{"affected": [{"affectedData": [{"product": "yeswiki", "vendor": "YesWiki", "versions": [{"status": "affected", "version": ">= 4.6.2, < 4.6.6"}]}], "source": "security-advisories@github.com"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "YesWiki is a wiki system written in PHP. From version 4.6.2 to before version 4.6.6, HttpSignatureService::verifySignature() checks the result of PHP's openssl_verify() with a loose boolean negation - if (!openssl_verify(...)) { throw ... }. PHP's openssl_verify has four possible return values: 1, 0, -1, and \"false\". The -1 row is the bypass: PHP's truthiness rules make -1 a truthy value, so !(-1) === false, the throw is skipped, and the controller proceeds to processActivity(). Any condition that makes OpenSSL's EVP_VerifyFinal() return -1 triggers the bypass. The reachable consequence is the controller silently treats a failed verification as success and processes the attacker's payload. This issue has been patched in version 4.6.6."}], "id": "CVE-2026-52767", "lastModified": "2026-09-05T00:17:19.540", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "LOW", "baseScore": 8.2, "baseSeverity": "HIGH", "confidentialityImpact": "NONE", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 4.2, "source": "security-advisories@github.com", "type": "Secondary"}]}, "published": "2026-09-05T00:17:19.540", "references": [{"source": "security-advisories@github.com", "url": "https://github.com/YesWiki/yeswiki/commit/d1795e0301e1a1078f17b4b98f56fff70de2029e"}, {"source": "security-advisories@github.com", "url": "https://github.com/YesWiki/yeswiki/releases/tag/v4.6.6"}, {"source": "security-advisories@github.com", "url": "https://github.com/YesWiki/yeswiki/security/advisories/GHSA-mv28-wj57-f57g"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-347"}], "source": "security-advisories@github.com", "type": "Primary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[4.6.2,4.6.6)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "yeswiki", "source": "cna", "vendor": "YesWiki"}, "product": "yeswiki", "vendor": "yeswiki"}], "created": "2026-09-05T00:30:18.579381+00:00", "updated": "2026-09-05T01:45:17.351686+00:00", "vendors": ["yeswiki", "yeswiki$PRODUCT$yeswiki"]}