CVE-2021-29492: Bypass of path matching rules using escaped slash characters
envoyproxy · envoy
Affected: envoyproxy · Exploitation: likely to be exploited (10% or more)
Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.
Higher than 99% of scored CVEs
DescriptionCVE.org
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.
Affected products1
From the CVE record. A product or version that is not listed is unknown, not unaffected.
- envoyproxy · envoy<= 1.18.2
On the Atlas
Every published CVE is on the CyberSIXT Atlas, grouped by weakness, vendor and month.
- Exploitation
- Likely to be exploited (10% or more). EPSS gives it a 10% or higher chance of exploitation in the next 30 days.
- CISA KEV
- Not listed
- Public check
- No public nuclei template
- Vendor
- envoyproxy
- Published
- May 2021
CoverageNo articles yet
No CyberSIXT article names CVE-2021-29492 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.