{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-33191", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "state": "PUBLISHED", "assignerShortName": "GitHub_M", "dateReserved": "2026-03-17T22:16:36.721Z", "datePublished": "2026-03-20T07:54:26.539Z", "dateUpdated": "2026-03-20T07:54:26.539Z"}, "containers": {"cna": {"title": "free5GC UDM vulnerable to null byte injection in URL path parameters causing 500 Internal Server Error", "problemTypes": [{"descriptions": [{"cweId": "CWE-158", "lang": "en", "description": "CWE-158: Improper Neutralization of Null Byte or NUL Character", "type": "CWE"}]}, {"descriptions": [{"cweId": "CWE-248", "lang": "en", "description": "CWE-248: Uncaught Exception", "type": "CWE"}]}], "metrics": [{"cvssV4_0": {"attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnAvailabilityImpact": "HIGH", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "baseScore": 8.7, "baseSeverity": "HIGH", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N", "version": "4.0"}}], "references": [{"name": "https://github.com/free5gc/free5gc/security/advisories/GHSA-p9hg-pq3q-v9gv", "tags": ["x_refsource_CONFIRM"], "url": "https://github.com/free5gc/free5gc/security/advisories/GHSA-p9hg-pq3q-v9gv"}, {"name": "https://github.com/free5gc/udm/commit/88de9fa74a1b3f3522e53b4cfa2d184712ffa4ee", "tags": ["x_refsource_MISC"], "url": "https://github.com/free5gc/udm/commit/88de9fa74a1b3f3522e53b4cfa2d184712ffa4ee"}], "affected": [{"vendor": "free5gc", "product": "free5gc", "versions": [{"version": "< 1.4.2", "status": "affected"}]}], "providerMetadata": {"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M", "dateUpdated": "2026-03-20T07:54:26.539Z"}, "descriptions": [{"lang": "en", "value": "Free5GC is an open-source Linux Foundation project for 5th generation (5G) mobile core networks. Versions prior to 1.4.2\nare vulnerable to null byte injection in URL path parameters. A remote attacker can inject null bytes (URL-encoded as %00) into the supi path parameter of the UDM's Nudm_SubscriberDataManagement API. This causes URL parsing failure in Go's net/url package with the error \"invalid control character in URL\", resulting in a 500 Internal Server Error. This null byte injection vulnerability can be exploited for denial of service attacks. When the supi parameter contains null characters, the UDM attempts to construct a URL for UDR that includes these control characters. Go's URL parser rejects them, causing the request to fail with 500 instead of properly validating input and returning 400 Bad Request. This issue has been fixed in version 1.4.2."}], "source": {"advisory": "GHSA-p9hg-pq3q-v9gv", "discovery": "UNKNOWN"}}}}

{}

{"cveTags": [], "descriptions": [{"lang": "en", "value": "Free5GC is an open-source Linux Foundation project for 5th generation (5G) mobile core networks. Versions prior to 1.4.2\nare vulnerable to null byte injection in URL path parameters. A remote attacker can inject null bytes (URL-encoded as %00) into the supi path parameter of the UDM's Nudm_SubscriberDataManagement API. This causes URL parsing failure in Go's net/url package with the error \"invalid control character in URL\", resulting in a 500 Internal Server Error. This null byte injection vulnerability can be exploited for denial of service attacks. When the supi parameter contains null characters, the UDM attempts to construct a URL for UDR that includes these control characters. Go's URL parser rejects them, causing the request to fail with 500 instead of properly validating input and returning 400 Bad Request. This issue has been fixed in version 1.4.2."}], "id": "CVE-2026-33191", "lastModified": "2026-03-20T08:16:12.597", "metrics": {"cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "NONE", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 8.7, "baseSeverity": "HIGH", "confidentialityRequirement": "NOT_DEFINED", "exploitMaturity": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "privilegesRequired": "NONE", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/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", "version": "4.0", "vulnAvailabilityImpact": "HIGH", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "security-advisories@github.com", "type": "Secondary"}]}, "published": "2026-03-20T08:16:12.597", "references": [{"source": "security-advisories@github.com", "url": "https://github.com/free5gc/free5gc/security/advisories/GHSA-p9hg-pq3q-v9gv"}, {"source": "security-advisories@github.com", "url": "https://github.com/free5gc/udm/commit/88de9fa74a1b3f3522e53b4cfa2d184712ffa4ee"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-158"}, {"lang": "en", "value": "CWE-248"}], "source": "security-advisories@github.com", "type": "Primary"}]}

{}

{"analysis": {"en": {"generated_at": "2026-03-20T09:27:07.825588+00:00", "value": {"mitigation_remediation": ["Upgrade free5GC UDM to version 1.4.2 or later"], "summary": {"action": "Apply Patch", "impact": "Denial of Service"}, "threat_synthesis": {"affected_systems": "Affected vendors and products: free5gc:free5gc UDM component. All versions before 1.4.2 are vulnerable. Upgrading to 1.4.2 or later resolves the issue.", "description_and_impact": "The vulnerability occurs when a remote attacker injects null bytes (%00) into the supi path parameter of the UDM's Nudm_SubscriberDataManagement API. This causes Go\u2019s net/url parser to reject the request with an \u201cinvalid control character in URL\u201d error, triggering a 500 Internal Server Error instead of a proper 400 Bad Request. The result is a denial\u2011of\u2011service condition for the targeted UDM instance. The weakness is consistent with CWE\u2011158 (Improper Neutralization of Special Elements in Output) and CWE\u2011248 (NULL Byte Injection).", "risk_and_exploitability": "The CVSS base score is 8.7, indicating high severity. EPSS score is not available, and the vulnerability is not listed in CISA\u2019s KEV catalog. The likely attack vector is remote over HTTP by sending a crafted URL to the UDM\u2019s Nudm_SubscriberDataManagement endpoint. No contractor exploits reported yet, but the high CVSS and lack of mitigation in older releases make it a significant risk for deployed systems."}}}}, "created": "2026-03-20T10:36:50.446898+00:00", "updated": "2026-03-20T10:36:50.446934+00:00", "vendors": []}