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| Vulnerability ID | VCID-u5y5-tcfd-aaan |
| Aliases |
CVE-2021-29492
|
| Summary | 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. |
| Status | Published |
| Exploitability | 0.5 |
| Weighted Severity | 9.0 |
| Risk | 4.5 |
| Affected and Fixed Packages | Package Details |
| Reference id | Reference type | URL |
|---|---|---|
| https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-29492.json | ||
| https://api.first.org/data/v1/epss?cve=CVE-2021-29492 | ||
| https://github.com/envoyproxy/envoy/security/advisories/GHSA-4987-27fx-x6cf | ||
| 1951188 | https://bugzilla.redhat.com/show_bug.cgi?id=1951188 | |
| AVG-1947 | https://security.archlinux.org/AVG-1947 | |
| cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:* | https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:* | |
| CVE-2021-29492 | https://nvd.nist.gov/vuln/detail/CVE-2021-29492 | |
| RHSA-2021:1538 | https://access.redhat.com/errata/RHSA-2021:1538 | |
| RHSA-2021:1540 | https://access.redhat.com/errata/RHSA-2021:1540 |
| Attack Vector (AV) | Attack Complexity (AC) | Privileges Required (PR) | User Interaction (UI) | Scope (S) | Confidentiality Impact (C) | Integrity Impact (I) | Availability Impact (A) |
|---|---|---|---|---|---|---|---|
network adjacent_network local physical |
low high |
none low high |
none required |
unchanged changed |
high low none |
high low none |
high low none |
| Exploitability (E) | Access Vector (AV) | Access Complexity (AC) | Authentication (Au) | Confidentiality Impact (C) | Integrity Impact (I) | Availability Impact (A) |
|---|---|---|---|---|---|---|
high functional unproven proof_of_concept not_defined |
local adjacent_network network |
high medium low |
multiple single none |
none partial complete |
none partial complete |
none partial complete |
| Attack Vector (AV) | Attack Complexity (AC) | Privileges Required (PR) | User Interaction (UI) | Scope (S) | Confidentiality Impact (C) | Integrity Impact (I) | Availability Impact (A) |
|---|---|---|---|---|---|---|---|
network adjacent_network local physical |
low high |
none low high |
none required |
unchanged changed |
high low none |
high low none |
high low none |
| Attack Vector (AV) | Attack Complexity (AC) | Privileges Required (PR) | User Interaction (UI) | Scope (S) | Confidentiality Impact (C) | Integrity Impact (I) | Availability Impact (A) |
|---|---|---|---|---|---|---|---|
network adjacent_network local physical |
low high |
none low high |
none required |
unchanged changed |
high low none |
high low none |
high low none |
| Percentile | 0.67268 |
| EPSS Score | 0.00268 |
| Published At | Dec. 17, 2024, midnight |
| Date | Actor | Action | Source | VulnerableCode Version |
|---|---|---|---|---|
| There are no relevant records. | ||||