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Vulnerability Details : 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.
Publish Date : 2021-05-28 Last Update Date : 2021-12-10
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- CVSS Scores & Vulnerability Types

CVSS Score
7.5
Confidentiality Impact Partial (There is considerable informational disclosure.)
Integrity Impact Partial (Modification of some system files or information is possible, but the attacker does not have control over what can be modified, or the scope of what the attacker can affect is limited.)
Availability Impact Partial (There is reduced performance or interruptions in resource availability.)
Access Complexity Low (Specialized access conditions or extenuating circumstances do not exist. Very little knowledge or skill is required to exploit. )
Authentication Not required (Authentication is not required to exploit the vulnerability.)
Gained Access None
Vulnerability Type(s) Directory traversalBypass a restriction or similar
CWE ID 22

- Products Affected By CVE-2021-29492

# Product Type Vendor Product Version Update Edition Language
1 Application Envoyproxy Envoy * * * * Version Details Vulnerabilities

- Number Of Affected Versions By Product

Vendor Product Vulnerable Versions
Envoyproxy Envoy 1

- References For CVE-2021-29492

https://github.com/envoyproxy/envoy/security/advisories/GHSA-4987-27fx-x6cf CONFIRM

- Metasploit Modules Related To CVE-2021-29492

There are not any metasploit modules related to this CVE entry (Please visit www.metasploit.com for more information)
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