CVE-2021-39156
published 2021-08-24CVE-2021-39156: Istio is an open source platform for providing a uniform way to integrate microservices, manage traffic flow across microservices, enforce policies and…
PriorityP343high7.5CVSS 3.1
AVNACLPRNUINSUCHINAN
EPSS
1.18%
67.4th percentile
Istio is an open source platform for providing a uniform way to integrate microservices, manage traffic flow across microservices, enforce policies and aggregate telemetry data. Istio 1.11.0, 1.10.3 and below, and 1.9.7 and below contain a remotely exploitable vulnerability where an HTTP request with `#fragment` in the path may bypass Istio’s URI path based authorization policies. Patches are available in Istio 1.11.1, Istio 1.10.4 and Istio 1.9.8. As a work around a Lua filter may be written to normalize the path.
Affected
10 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| github.com | traefik_traefik_v2 | >= 0 < 2.11.57 | 2.11.57 |
| github.com | traefik_traefik_v3 | >= 3.0.0 < 3.7.13 | 3.7.13 |
| istio.io | istio | >= 0 < 1.9.8 | 1.9.8 |
| istio.io | istio | >= 1.10.0 < 1.10.4 | 1.10.4 |
| istio.io | istio | >= 1.11.0 < 1.11.1 | 1.11.1 |
| istio | istio | < 1.9.8 | 1.9.8 |
| istio | istio | — | — |
| istio | istio | — | — |
| istio | istio | >= 1.10.0 < 1.10.3 | 1.10.3 |
| istio | istio | >= 1.11.0 < 1.11.1 | 1.11.1 |
CVSS provenance
nvdv3.17.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
nvdv2.05.0MEDIUMAV:N/AC:L/Au:N/C:P/I:N/A:N
vendor_redhat8.1HIGH
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Red Hat
istio/istio: HTTP request with fragment in URI can bypass authorization mechanisms
vendor_redhat·2021-08-24·CVSS 8.1
CVE-2021-39156 [HIGH] CWE-863 istio/istio: HTTP request with fragment in URI can bypass authorization mechanisms
istio/istio: HTTP request with fragment in URI can bypass authorization mechanisms
Istio is an open source platform for providing a uniform way to integrate microservices, manage traffic flow across microservices, enforce policies and aggregate telemetry data. Istio 1.11.0, 1.10.3 and below, and 1.9.7 and below contain a remotely exploitable vulnerability where an HTTP request with `#fragment` in the path may bypass Istio’s URI path based authorization policies. Patches are available in Istio 1.11.1, Istio 1.10.4 and Istio 1.9.8. As a work around a Lua filter may be written to normalize the path.
An authorization bypass vulnerability was found in istio/istio. An HTTP request is incorrectly evaluated when a URI #fragment is specified. This flaw allows an attacker to bypass an Istio URI-ba
GHSA
Traefik: Rootless HTTP/1 request-target routes as "/" but is forwarded verbatim, bypassing path-scoped routing, middleware guards and access logging
ghsa·2026-09-10
CVE-2026-88009 [HIGH] CWE-1286 Traefik: Rootless HTTP/1 request-target routes as "/" but is forwarded verbatim, bypassing path-scoped routing, middleware guards and access logging
Traefik: Rootless HTTP/1 request-target routes as "/" but is forwarded verbatim, bypassing path-scoped routing, middleware guards and access logging
## Summary
Traefik accepts an HTTP/1.x request whose request-target is in rootless / opaque form (for example `GET http:http://internal-vhost/admin HTTP/1.1`). Go parses this into `URL.Opaque` with an empty `URL.Path`, so Traefik evaluates all routing, path-sanitization, middleware and access-log decisions against a path that normalizes to `/`, while the proxy forwards the attacker's original target byte-for-byte to the backend. Router path/prefix guards, `forwardAuth` path-scoped policies and the `encodedCharacters` hardening never see the real target, and the access log records every such request as `GET / HTTP/1.1`. Against a backend that
GHSA
Istio Fragments in Path May Lead to Authorization Policy Bypass
ghsa·2021-08-30
CVE-2021-39156 [HIGH] CWE-706 Istio Fragments in Path May Lead to Authorization Policy Bypass
Istio Fragments in Path May Lead to Authorization Policy Bypass
### Impact
Istio 1.11.0, 1.10.3 and below, and 1.9.7 and below contain a remotely exploitable vulnerability where an HTTP request with `#fragment` in the path may bypass Istio’s URI path based authorization policies.
### Patches
* Istio 1.11.1 and above
* Istio 1.10.4 and above
* Istio 1.9.8 and above
### Workarounds
A Lua filter may be written to normalize the path. This is similar to the Path normalization presented in the [Security Best Practices](https://istio.io/latest/docs/ops/best-practices/security/#case-normalization) guide.
### References
More details can be found in the [Istio Security Bulletin](https://istio.io/latest/news/security/istio-security-2021-008)
### For more information
If you have any questions or
OSV
Istio Fragments in Path May Lead to Authorization Policy Bypass
osv·2021-08-30
CVE-2021-39156 [HIGH] Istio Fragments in Path May Lead to Authorization Policy Bypass
Istio Fragments in Path May Lead to Authorization Policy Bypass
### Impact
Istio 1.11.0, 1.10.3 and below, and 1.9.7 and below contain a remotely exploitable vulnerability where an HTTP request with `#fragment` in the path may bypass Istio’s URI path based authorization policies.
### Patches
* Istio 1.11.1 and above
* Istio 1.10.4 and above
* Istio 1.9.8 and above
### Workarounds
A Lua filter may be written to normalize the path. This is similar to the Path normalization presented in the [Security Best Practices](https://istio.io/latest/docs/ops/best-practices/security/#case-normalization) guide.
### References
More details can be found in the [Istio Security Bulletin](https://istio.io/latest/news/security/istio-security-2021-008)
### For more information
If you have any questions or
No detection rules found.
No public exploits indexed.
No writeups or analysis indexed.
2021-08-24
Published