CVE-2023-35941 Envoy vulnerable to OAuth2 credentials exploit with permanent validity

What is CVE-2023-35941?

CVE-2023-35941 is a high-severity authentication bypass vulnerability in Envoyproxy Envoy, published on 25 Jul 2023. 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. Prior to versions 1.27.0, 1.26.4, 1.25.9, 1.24.10, and 1.23.12, a malicious client is able to construct credentials with permanent validity in some specific scenarios. This is caused by the some rare scenarios in which HMAC payload can be always valid in OAuth2 filter's check. Versions 1.27.0, 1.26.4, 1.25.9, 1.24.10, and 1.23.12 have a fix for this issue. As a workaround, avoid wildcards/prefix domain wildcards in the host's domain configuration.

Weakness: CWE-116

Which versions are affected by CVE-2023-35941?

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

Products include Envoyproxy Envoy.

How do I fix CVE-2023-35941?

Upgrade envoy to a fixed version for your release line: 1.23.12, 1.24.10, 1.25.9 or 1.26.4.

Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.

Is CVE-2023-35941 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-35941 exists.

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-2023-35941, GHSA-7mhv-gr67-hq55.