CVE-2023-35942 Envoy's gRPC access log crash caused by the listener draining

What is CVE-2023-35942?

CVE-2023-35942 is a medium-severity use after free vulnerability in Envoyproxy Envoy, published on 25 Jul 2023. Any signed-in user can exploit it over the network, 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, gRPC access loggers using listener's global scope can cause a `use-after-free` crash when the listener is drained. 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, disable gRPC access log or stop listener update.

Weakness: CWE-416

Which versions are affected by CVE-2023-35942?

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

Products include Envoyproxy Envoy.

How do I fix CVE-2023-35942?

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

Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.

Is CVE-2023-35942 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-35942 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-2023-35942, GHSA-69vr-g55c-v2v4.