CVE-2021-29492 — Path Traversal in Envoy

CWE-22 — Path TraversalCWE-863 — Incorrect Authorization3 documents2 sources
Severity
8.3HIGHNVD
EPSS
10.5%
top 6.74%
CISA KEV
Not in KEV
Exploit
No known exploits
Affected products
1
Envoyproxy Envoy
Timeline
Latest updateMay 11
PublishedMay 28

Description

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 …

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:LExploitability: 3.9 | Impact: 3.7

Affected Packages2 packages

▶NVDenvoyproxy/envoy1.16.0 — 1.16.4+3
▶CVEListV5envoyproxy/envoy1.18.2

📋Vendor Advisories

2
Red Hat
istio/istio: HTTP request with escaped slash characters can bypass authorization mechanisms↗2021-05-11
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Red Hat
envoyproxy/envoy: HTTP request with escaped slash characters can bypass Envoy's authorization mechanisms↗2021-05-11
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CVE-2021-29492 — Path Traversal in Envoyproxy Envoy | cvebase