#VU56147 Excessive Iteration in envoy - CVE-2021-32778

Vulnerability identifier: #VU56147

Vulnerability risk: Medium

CVSSv4.0: 2.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2021-32778

CWE-ID: CWE-834

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
envoy
Server applications / IDS/IPS systems, Firewalls and proxy servers

Vendor: Cloud Native Computing Foundation

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to the Envoy is configured with high limit on H/2 concurrent streams. A remote attacker can cause a denial of service condition on the target system. 

Mitigation
Install updates from vendor's website.

Vulnerable software versions

envoy: 1.16.0 - 1.19.0

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External links
https://www.envoyproxy.io/docs/envoy/v1.19.0/version_history/version_history
https://github.com/envoyproxy/envoy/security/advisories/GHSA-3xh3-33v5-chcc

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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.