Vulnerability identifier: #VU56151

Vulnerability risk: High

CVSSv3.1: 7.1 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-39156

CWE-ID: CWE-285

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Istio
Web applications / Other software

Vendor: Istio

Description

The vulnerability allows a remote attacker to bypass authorization checks.

The vulnerability exists due to insufficient authorization checks. A remote attacker can send a specially crafted HTTP request with #fragment in the path and bypass authorization on the target system.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Istio: 1.9.0 - 1.11.0

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External links
http://istio.io/latest/news/security/istio-security-2021-008
http://github.com/istio/istio/security/advisories/GHSA-hqxw-mm44-gc4r

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.