Use After Free in Envoyproxy Envoy

CVE-2023-35943

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, the CORS filter will segfault and crash Envoy when the `origin` header is removed and deleted between `decodeHeaders`and `encodeHeaders`. 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, do not remove the `origin` header in the Envoy configuration.

Vulnerability class: Use-After-Free

Published · last modified .

CVSS v3 metric

CVSS v3 base score 6.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:H.

EPSS exploit prediction

EPSS: 0.007 (49.6th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 50th percentile — 49.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2023-35943: held from 0.007 to 0.007.

EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: 0.000

Affected products

  • Envoyproxy Envoy — versions >= 1.26.0, < 1.26.4, >= 1.25.0, < 1.25.9, >= 1.24.0, < 1.24.10

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2023-35943?
CVE-2023-35943 is a medium-severity vulnerability in Envoyproxy Envoy, classified under Use After Free. CVSS score: 6.3/10. Published 2023-07-25.
How severe is CVE-2023-35943?
Medium severity. CVSS v3 base score is 6.3 out of 10.