Use After Free in Envoyproxy Envoy
CVE-2021-43826
Envoy is an open source edge and service proxy, designed for cloud-native applications. In affected versions of Envoy a crash occurs when configured for :ref:`upstream tunneling <envoy_v3_api_field_extensions.filters.network.tcp_proxy.v3.TcpProxy.tunneling_config>` and the downstream connection disconnects while the the upstream connection or http/2 stream is still being established. There are no workarounds for this issue. Users are advised to upgrade.
Vulnerability class: Use-After-Free
EPSS: 0.011 (61.2th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
Affected products
- Envoyproxy Envoy — versions < 1.18.6, >= 1.19.0, < 1.19.3, >= 1.20.0, < 1.20.2
Weakness classification (CWE)
Public proof-of-concept exploits
References
- security-advisories@github.com (x_refsource_CONFIRM, Third Party Advisory, Issue Tracking)
- security-advisories@github.com (Patch, Third Party Advisory, x_refsource_MISC)
Frequently asked questions
- What is CVE-2021-43826?
- CVE-2021-43826 is a high-severity vulnerability in Envoyproxy Envoy, classified under Use After Free. CVSS score: 7.5/10. Published 2022-02-22.
- How severe is CVE-2021-43826?
- High severity. CVSS v3 base score is 7.5 out of 10.
- Is CVE-2021-43826 known to be exploited?
- 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.