CVE-2021-21404

{"containers": {"cna": {"affected": [{"product": "syncthing", "vendor": "syncthing", "versions": [{"status": "affected", "version": "< 1.15.0"}]}], "descriptions": [{"lang": "en", "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."}], "metrics": [{"cvssV3_1": {"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"}}], "problemTypes": [{"descriptions": [{"cweId": "CWE-20", "description": "CWE-20 Improper Input Validation", "lang": "en", "type": "CWE"}]}], "providerMetadata": {"dateUpdated": "2021-04-06T20:00:15.000Z", "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M"}, "references": [{"tags": ["x_refsource_CONFIRM"], "url": "https://github.com/syncthing/syncthing/security/advisories/GHSA-x462-89pf-6r5h"}, {"tags": ["x_refsource_MISC"], "url": "https://pkg.go.dev/github.com/syncthing/syncthing"}, {"tags": ["x_refsource_MISC"], "url": "https://github.com/syncthing/syncthing/commit/fb4fdaf4c0a79c22cad000c42ac1394e3ccb6a97"}, {"tags": ["x_refsource_MISC"], "url": "https://github.com/syncthing/syncthing/releases/tag/v1.15.0"}], "source": {"advisory": "GHSA-x462-89pf-6r5h", "discovery": "UNKNOWN"}, "title": "Crash due to malformed relay protocol message", "x_legacyV4Record": {"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"}}}, "adp": [{"providerMetadata": {"orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2024-08-03T18:09:16.158Z"}, "title": "CVE Program Container", "references": [{"tags": ["x_refsource_CONFIRM", "x_transferred"], "url": "https://github.com/syncthing/syncthing/security/advisories/GHSA-x462-89pf-6r5h"}, {"tags": ["x_refsource_MISC", "x_transferred"], "url": "https://pkg.go.dev/github.com/syncthing/syncthing"}, {"tags": ["x_refsource_MISC", "x_transferred"], "url": "https://github.com/syncthing/syncthing/commit/fb4fdaf4c0a79c22cad000c42ac1394e3ccb6a97"}, {"tags": ["x_refsource_MISC", "x_transferred"], "url": "https://github.com/syncthing/syncthing/releases/tag/v1.15.0"}]}]}, "cveMetadata": {"assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "assignerShortName": "GitHub_M", "cveId": "CVE-2021-21404", "datePublished": "2021-04-06T20:00:15.000Z", "dateReserved": "2020-12-22T00:00:00.000Z", "dateUpdated": "2024-08-03T18:09:16.158Z", "state": "PUBLISHED"}, "dataType": "CVE_RECORD", "dataVersion": "5.1"}

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{"affected": [{"affectedData": [{"product": "syncthing", "vendor": "syncthing", "versions": [{"status": "affected", "version": "< 1.15.0"}]}], "source": "security-advisories@github.com"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:syncthing:syncthing:*:*:*:*:*:*:*:*", "matchCriteriaId": "13E0DFD1-14D6-4A2D-B98C-1C581D11E2F0", "versionEndExcluding": "1.15.0", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "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."}, {"lang": "es", "value": "Syncthing es un programa de sincronizaci\u00f3n de archivos continua.&#xa0;En Syncthing versiones anteriores a 1.15.0, el servidor de retransmisi\u00f3n \"strelaysrv\" puede causar un bloqueo y salida mediante el env\u00edo de un mensaje de retransmisi\u00f3n con un campo de longitud negativa.&#xa0;De manera similar, Syncthing en s\u00ed puede presentar un fallo por la misma raz\u00f3n si recibe un mensaje malformado de un servidor de retransmisi\u00f3n malicioso al intentar unirse a la retransmisi\u00f3n.&#xa0;Las uniones de retransmisiones son esencialmente aleatorias (de un subconjunto de retransmisiones de baja latencia) y Syncthing se reiniciar\u00e1 por defecto cuando se bloquee, momento en el que es probable que elija otra retransmisi\u00f3n no maliciosa.&#xa0;Este fallo es corregido en la versi\u00f3n 1.15.0"}], "id": "CVE-2021-21404", "lastModified": "2026-06-17T03:35:30.003", "metrics": {"cvssMetricV2": [{"acInsufInfo": false, "baseSeverity": "MEDIUM", "cvssData": {"accessComplexity": "LOW", "accessVector": "NETWORK", "authentication": "NONE", "availabilityImpact": "PARTIAL", "baseScore": 5.0, "confidentialityImpact": "NONE", "integrityImpact": "NONE", "vectorString": "AV:N/AC:L/Au:N/C:N/I:N/A:P", "version": "2.0"}, "exploitabilityScore": 10.0, "impactScore": 2.9, "obtainAllPrivilege": false, "obtainOtherPrivilege": false, "obtainUserPrivilege": false, "source": "nvd@nist.gov", "type": "Primary", "userInteractionRequired": false}], "cvssMetricV31": [{"cvssData": {"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"}, "exploitabilityScore": 3.9, "impactScore": 3.6, "source": "security-advisories@github.com", "type": "Secondary"}, {"cvssData": {"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"}, "exploitabilityScore": 3.9, "impactScore": 3.6, "source": "nvd@nist.gov", "type": "Primary"}]}, "published": "2021-04-06T20:15:13.490", "references": [{"source": "security-advisories@github.com", "tags": ["Patch", "Third Party Advisory"], "url": "https://github.com/syncthing/syncthing/commit/fb4fdaf4c0a79c22cad000c42ac1394e3ccb6a97"}, {"source": "security-advisories@github.com", "tags": ["Release Notes", "Third Party Advisory"], "url": "https://github.com/syncthing/syncthing/releases/tag/v1.15.0"}, {"source": "security-advisories@github.com", "tags": ["Third Party Advisory"], "url": "https://github.com/syncthing/syncthing/security/advisories/GHSA-x462-89pf-6r5h"}, {"source": "security-advisories@github.com", "tags": ["Product", "Third Party Advisory"], "url": "https://pkg.go.dev/github.com/syncthing/syncthing"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Patch", "Third Party Advisory"], "url": "https://github.com/syncthing/syncthing/commit/fb4fdaf4c0a79c22cad000c42ac1394e3ccb6a97"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Release Notes", "Third Party Advisory"], "url": "https://github.com/syncthing/syncthing/releases/tag/v1.15.0"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Third Party Advisory"], "url": "https://github.com/syncthing/syncthing/security/advisories/GHSA-x462-89pf-6r5h"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Product", "Third Party Advisory"], "url": "https://pkg.go.dev/github.com/syncthing/syncthing"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Modified", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-20"}], "source": "security-advisories@github.com", "type": "Secondary"}]}

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