CVE-2021-29492

{"containers": {"cna": {"affected": [{"product": "envoy", "vendor": "envoyproxy", "versions": [{"status": "affected", "version": "<= 1.18.2"}]}], "descriptions": [{"lang": "en", "value": "Envoy is a cloud-native edge/middle/service proxy. Envoy does not decode escaped slash sequences `%2F` and `%5C` in HTTP URL paths in versions 1.18.2 and before. A remote attacker may craft a path with escaped slashes, e.g. `/something%2F..%2Fadmin`, to bypass access control, e.g. a block on `/admin`. A backend server could then decode slash sequences and normalize path and provide an attacker access beyond the scope provided for by the access control policy. ### Impact Escalation of Privileges when using RBAC or JWT filters with enforcement based on URL path. Users with back end servers that interpret `%2F` and `/` and `%5C` and `\\` interchangeably are impacted. ### Attack Vector URL paths containing escaped slash characters delivered by untrusted client. Patches in versions 1.18.3, 1.17.3, 1.16.4, 1.15.5 contain new path normalization option to decode escaped slash characters. As a workaround, if back end servers treat `%2F` and `/` and `%5C` and `\\` interchangeably and a URL path based access control is configured, one may reconfigure the back end server to not treat `%2F` and `/` and `%5C` and `\\` interchangeably."}], "metrics": [{"cvssV3_1": {"attackComplexity": "HIGH", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 8.1, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}}], "problemTypes": [{"descriptions": [{"cweId": "CWE-22", "description": "CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')", "lang": "en", "type": "CWE"}]}], "providerMetadata": {"dateUpdated": "2021-06-07T11:25:20.000Z", "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M"}, "references": [{"tags": ["x_refsource_CONFIRM"], "url": "https://github.com/envoyproxy/envoy/security/advisories/GHSA-4987-27fx-x6cf"}], "source": {"advisory": "GHSA-4987-27fx-x6cf", "discovery": "UNKNOWN"}, "title": "Bypass of path matching rules using escaped slash characters", "x_legacyV4Record": {"CVE_data_meta": {"ASSIGNER": "security-advisories@github.com", "ID": "CVE-2021-29492", "STATE": "PUBLIC", "TITLE": "Bypass of path matching rules using escaped slash characters"}, "affects": {"vendor": {"vendor_data": [{"product": {"product_data": [{"product_name": "envoy", "version": {"version_data": [{"version_value": "<= 1.18.2"}]}}]}, "vendor_name": "envoyproxy"}]}}, "data_format": "MITRE", "data_type": "CVE", "data_version": "4.0", "description": {"description_data": [{"lang": "eng", "value": "Envoy is a cloud-native edge/middle/service proxy. Envoy does not decode escaped slash sequences `%2F` and `%5C` in HTTP URL paths in versions 1.18.2 and before. A remote attacker may craft a path with escaped slashes, e.g. `/something%2F..%2Fadmin`, to bypass access control, e.g. a block on `/admin`. A backend server could then decode slash sequences and normalize path and provide an attacker access beyond the scope provided for by the access control policy. ### Impact Escalation of Privileges when using RBAC or JWT filters with enforcement based on URL path. Users with back end servers that interpret `%2F` and `/` and `%5C` and `\\` interchangeably are impacted. ### Attack Vector URL paths containing escaped slash characters delivered by untrusted client. Patches in versions 1.18.3, 1.17.3, 1.16.4, 1.15.5 contain new path normalization option to decode escaped slash characters. As a workaround, if back end servers treat `%2F` and `/` and `%5C` and `\\` interchangeably and a URL path based access control is configured, one may reconfigure the back end server to not treat `%2F` and `/` and `%5C` and `\\` interchangeably."}]}, "impact": {"cvss": {"attackComplexity": "HIGH", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 8.1, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}}, "problemtype": {"problemtype_data": [{"description": [{"lang": "eng", "value": "CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')"}]}]}, "references": {"reference_data": [{"name": "https://github.com/envoyproxy/envoy/security/advisories/GHSA-4987-27fx-x6cf", "refsource": "CONFIRM", "url": "https://github.com/envoyproxy/envoy/security/advisories/GHSA-4987-27fx-x6cf"}]}, "source": {"advisory": "GHSA-4987-27fx-x6cf", "discovery": "UNKNOWN"}}}, "adp": [{"providerMetadata": {"orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2024-08-03T22:11:05.253Z"}, "title": "CVE Program Container", "references": [{"tags": ["x_refsource_CONFIRM", "x_transferred"], "url": "https://github.com/envoyproxy/envoy/security/advisories/GHSA-4987-27fx-x6cf"}]}]}, "cveMetadata": {"assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "assignerShortName": "GitHub_M", "cveId": "CVE-2021-29492", "datePublished": "2021-05-28T21:00:24.000Z", "dateReserved": "2021-03-30T00:00:00.000Z", "dateUpdated": "2024-08-03T22:11:05.253Z", "state": "PUBLISHED"}, "dataType": "CVE_RECORD", "dataVersion": "5.1"}

{}

{"affected": [{"affectedData": [{"product": "envoy", "vendor": "envoyproxy", "versions": [{"status": "affected", "version": "<= 1.18.2"}]}], "source": "security-advisories@github.com"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*", "matchCriteriaId": "EE9E311E-85FF-42AA-B0A3-C138D436932D", "versionEndExcluding": "1.15.5", "vulnerable": true}, {"criteria": "cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*", "matchCriteriaId": "D36D66BB-9C95-4E59-AA78-6824ACCB89D7", "versionEndExcluding": "1.16.4", "versionStartIncluding": "1.16.0", "vulnerable": true}, {"criteria": "cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*", "matchCriteriaId": "D502D5F9-38A7-46B1-890D-2A177B76AEBB", "versionEndExcluding": "1.17.3", "versionStartIncluding": "1.17.0", "vulnerable": true}, {"criteria": "cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*", "matchCriteriaId": "BA3D8EC7-7D60-41C5-9770-3521DB6F7650", "versionEndExcluding": "1.18.3", "versionStartIncluding": "1.18.0", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "Envoy is a cloud-native edge/middle/service proxy. Envoy does not decode escaped slash sequences `%2F` and `%5C` in HTTP URL paths in versions 1.18.2 and before. A remote attacker may craft a path with escaped slashes, e.g. `/something%2F..%2Fadmin`, to bypass access control, e.g. a block on `/admin`. A backend server could then decode slash sequences and normalize path and provide an attacker access beyond the scope provided for by the access control policy. ### Impact Escalation of Privileges when using RBAC or JWT filters with enforcement based on URL path. Users with back end servers that interpret `%2F` and `/` and `%5C` and `\\` interchangeably are impacted. ### Attack Vector URL paths containing escaped slash characters delivered by untrusted client. Patches in versions 1.18.3, 1.17.3, 1.16.4, 1.15.5 contain new path normalization option to decode escaped slash characters. As a workaround, if back end servers treat `%2F` and `/` and `%5C` and `\\` interchangeably and a URL path based access control is configured, one may reconfigure the back end server to not treat `%2F` and `/` and `%5C` and `\\` interchangeably."}, {"lang": "es", "value": "Envoy es un proxy de borde/medio/servicio nativo de la nube. Envoy no descifra las secuencias de barras diagonales escapadas `%2F` y `%5C` en las rutas URL HTTP en las versiones 1.18.2 y anteriores. Un atacante remoto puede crear una ruta con barras escapadas, por ejemplo `algo%2F..%2Fadmin`, para saltarse el control de acceso, por ejemplo, un bloqueo en `/admin`. Un servidor backend podr\u00eda entonces decodificar las secuencias de barras y normalizar la ruta y proporcionar a un atacante acceso m\u00e1s all\u00e1 del alcance previsto por la pol\u00edtica de control de acceso. ### Impacto Escalada de Privilegios cuando se utilizan filtros RBAC o JWT con aplicaci\u00f3n basada en la ruta de la URL. Los usuarios con servidores de back-end que interpretan `%2F` y `/` y `%5C` y `\\` indistintamente est\u00e1n impactados. ### Vector de ataque Rutas de URL que contienen caracteres de barra diagonal escapados entregados por un cliente que no es de confianza. Los parches de las versiones 1.18.3, 1.17.3, 1.16.4 y 1.15.5 contienen una nueva opci\u00f3n de normalizaci\u00f3n de rutas para descodificar los caracteres de barra diagonal escapados. Como soluci\u00f3n, si los servidores finales tratan `%2F` y `/` y `%5C` y `\\` indistintamente y se configura un control de acceso basado en la ruta de la URL, se puede reconfigurar el servidor final para que no trate `%2F` y `/` y `%5C` y `\\` indistintamente"}], "id": "CVE-2021-29492", "lastModified": "2026-06-17T03:47:45.130", "metrics": {"cvssMetricV2": [{"acInsufInfo": false, "baseSeverity": "HIGH", "cvssData": {"accessComplexity": "LOW", "accessVector": "NETWORK", "authentication": "NONE", "availabilityImpact": "PARTIAL", "baseScore": 7.5, "confidentialityImpact": "PARTIAL", "integrityImpact": "PARTIAL", "vectorString": "AV:N/AC:L/Au:N/C:P/I:P/A:P", "version": "2.0"}, "exploitabilityScore": 10.0, "impactScore": 6.4, "obtainAllPrivilege": false, "obtainOtherPrivilege": false, "obtainUserPrivilege": false, "source": "nvd@nist.gov", "type": "Primary", "userInteractionRequired": false}], "cvssMetricV31": [{"cvssData": {"attackComplexity": "HIGH", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 8.1, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 2.2, "impactScore": 5.9, "source": "security-advisories@github.com", "type": "Secondary"}, {"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "LOW", "baseScore": 8.3, "baseSeverity": "HIGH", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "privilegesRequired": "NONE", "scope": "CHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 3.7, "source": "nvd@nist.gov", "type": "Primary"}]}, "published": "2021-05-28T21:15:08.670", "references": [{"source": "security-advisories@github.com", "tags": ["Mitigation", "Third Party Advisory"], "url": "https://github.com/envoyproxy/envoy/security/advisories/GHSA-4987-27fx-x6cf"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Mitigation", "Third Party Advisory"], "url": "https://github.com/envoyproxy/envoy/security/advisories/GHSA-4987-27fx-x6cf"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Modified", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-22"}], "source": "security-advisories@github.com", "type": "Secondary"}]}

{"acknowledgement": "Red Hat would like to thank the Envoy security team for reporting this issue.", "affected_release": [{"advisory": "RHSA-2021:1540", "cpe": "cpe:/a:redhat:service_mesh:1.1::el8", "package": "servicemesh-proxy-0:1.1.14-1.el8", "product_name": "OpenShift Service Mesh 1.1", "release_date": "2021-05-11T00:00:00Z"}, {"advisory": "RHSA-2021:1538", "cpe": "cpe:/a:redhat:service_mesh:2.0::el8", "package": "servicemesh-operator-0:2.0.4-3.el8", "product_name": "OpenShift Service Mesh 2.0", "release_date": "2021-05-11T00:00:00Z"}, {"advisory": "RHSA-2021:1538", "cpe": "cpe:/a:redhat:service_mesh:2.0::el8", "package": "servicemesh-proxy-0:2.0.4-1.el8", "product_name": "OpenShift Service Mesh 2.0", "release_date": "2021-05-11T00:00:00Z"}], "bugzilla": {"description": "envoyproxy/envoy: HTTP request with escaped slash characters can bypass Envoy's authorization mechanisms", "id": "1951188", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=1951188"}, "csaw": false, "cvss3": {"cvss3_base_score": "8.3", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L", "status": "verified"}, "cwe": "CWE-863", "details": ["Envoy is a cloud-native edge/middle/service proxy. Envoy does not decode escaped slash sequences `%2F` and `%5C` in HTTP URL paths in versions 1.18.2 and before. A remote attacker may craft a path with escaped slashes, e.g. `/something%2F..%2Fadmin`, to bypass access control, e.g. a block on `/admin`. A backend server could then decode slash sequences and normalize path and provide an attacker access beyond the scope provided for by the access control policy. ### Impact Escalation of Privileges when using RBAC or JWT filters with enforcement based on URL path. Users with back end servers that interpret `%2F` and `/` and `%5C` and `\\` interchangeably are impacted. ### Attack Vector URL paths containing escaped slash characters delivered by untrusted client. Patches in versions 1.18.3, 1.17.3, 1.16.4, 1.15.5 contain new path normalization option to decode escaped slash characters. As a workaround, if back end servers treat `%2F` and `/` and `%5C` and `\\` interchangeably and a URL path based access control is configured, one may reconfigure the back end server to not treat `%2F` and `/` and `%5C` and `\\` interchangeably.", "An authorization bypass vulnerability was found in envoyproxy/envoy. An attacker can potentially craft an HTTP request that defines a certain pattern of escaped characters in the URI path (such as %2F, %2f, %5C or %5c), allowing them to bypass the envoy authorization service. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability."], "name": "CVE-2021-29492", "public_date": "2021-05-11T19:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2021-29492\nhttps://nvd.nist.gov/vuln/detail/CVE-2021-29492\nhttps://istio.io/latest/news/releases/1.9.x/announcing-1.9.5/"], "threat_severity": "Important"}

{}