8.3

CVE-2021-29492

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.

Data is provided by the National Vulnerability Database (NVD)
Envoyproxy ≫ Envoy Version < 1.15.5
Envoyproxy ≫ Envoy Version >= 1.16.0 < 1.16.4
Envoyproxy ≫ Envoy Version >= 1.17.0 < 1.17.3
Envoyproxy ≫ Envoy Version >= 1.18.0 < 1.18.3
Zu dieser CVE wurde keine CISA KEV oder CERT.AT-Warnung gefunden.
EPSS Metriken
Type Source Score Percentile
EPSS FIRST.org 7.42% 0.908
CVSS Metriken
Source Base Score Exploit Score Impact Score Vector string
nvd@nist.gov 8.3 3.9 3.7
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L
nvd@nist.gov 7.5 10 6.4
AV:N/AC:L/Au:N/C:P/I:P/A:P
security-advisories@github.com 8.1 2.2 5.9
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
CWE-22 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.