CVE-2021-43824 Null pointer dereference in envoy

What is CVE-2021-43824?

CVE-2021-43824 is a high-severity vulnerability in Envoyproxy Envoy, published on 22 Feb 2022. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Envoy is an open source edge and service proxy, designed for cloud-native applications. In affected versions a crafted request crashes Envoy when a CONNECT request is sent to JWT filter configured with regex match. This provides a denial of service attack vector. The only workaround is to not use regex in the JWT filter. Users are advised to upgrade.

Weakness: CWE-476

Which versions are affected by CVE-2021-43824?

1 open source package ship an affected version, including envoy. It affects 1 product.

Products include Envoyproxy Envoy.

How do I fix CVE-2021-43824?

Upgrade envoy to a fixed version for your release line: 1.18.6, 1.19.3, 1.20.2 or 1.21.1.

Is CVE-2021-43824 being exploited?

There is no known exploitation of CVE-2021-43824 in the wild and no public exploit code.

Other vulnerabilities in Envoyproxy Envoy

• CVE-2022-29226 Trivial authentication bypass in Envoy Critical 10.0
• CVE-2019-18801 Memory corruption in n/a Critical 9.8
• CVE-2019-18802 Security feature bypass in n/a Critical 9.8
• CVE-2020-35470 Information disclosure in n/a High 8.8
• CVE-2024-23324 Envoy ext auth can be bypassed when Proxy protocol filter sets invalid UTF-8 metadata High 8.6

All Envoyproxy Envoy vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as BIT-envoy-2021-43824, GHSA-vj5m-rch8-5r2p.