{
    "CVE_data_meta": {
        "ASSIGNER": "security-advisories@github.com",
        "ID": "CVE-2021-21404",
        "STATE": "PUBLIC",
        "TITLE": "Crash due to malformed relay protocol message"
    },
    "affects": {
        "vendor": {
            "vendor_data": [
                {
                    "product": {
                        "product_data": [
                            {
                                "product_name": "syncthing",
                                "version": {
                                    "version_data": [
                                        {
                                            "version_value": "< 1.15.0"
                                        }
                                    ]
                                }
                            }
                        ]
                    },
                    "vendor_name": "syncthing"
                }
            ]
        }
    },
    "data_format": "MITRE",
    "data_type": "CVE",
    "data_version": "4.0",
    "description": {
        "description_data": [
            {
                "lang": "eng",
                "value": "Syncthing is a continuous file synchronization program. In Syncthing before version 1.15.0, the relay server `strelaysrv` can be caused to crash and exit by sending a relay message with a negative length field. Similarly, Syncthing itself can crash for the same reason if given a malformed message from a malicious relay server when attempting to join the relay. Relay joins are essentially random (from a subset of low latency relays) and Syncthing will by default restart when crashing, at which point it's likely to pick another non-malicious relay. This flaw is fixed in version 1.15.0."
            }
        ]
    },
    "impact": {
        "cvss": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
        }
    },
    "problemtype": {
        "problemtype_data": [
            {
                "description": [
                    {
                        "lang": "eng",
                        "value": "CWE-20 Improper Input Validation"
                    }
                ]
            }
        ]
    },
    "references": {
        "reference_data": [
            {
                "name": "https://github.com/syncthing/syncthing/security/advisories/GHSA-x462-89pf-6r5h",
                "refsource": "CONFIRM",
                "url": "https://github.com/syncthing/syncthing/security/advisories/GHSA-x462-89pf-6r5h"
            },
            {
                "name": "https://pkg.go.dev/github.com/syncthing/syncthing",
                "refsource": "MISC",
                "url": "https://pkg.go.dev/github.com/syncthing/syncthing"
            },
            {
                "name": "https://github.com/syncthing/syncthing/commit/fb4fdaf4c0a79c22cad000c42ac1394e3ccb6a97",
                "refsource": "MISC",
                "url": "https://github.com/syncthing/syncthing/commit/fb4fdaf4c0a79c22cad000c42ac1394e3ccb6a97"
            },
            {
                "name": "https://github.com/syncthing/syncthing/releases/tag/v1.15.0",
                "refsource": "MISC",
                "url": "https://github.com/syncthing/syncthing/releases/tag/v1.15.0"
            }
        ]
    },
    "source": {
        "advisory": "GHSA-x462-89pf-6r5h",
        "discovery": "UNKNOWN"
    }
}