What is CVE-2021-43824?

CVE-2021-43824 is a high-severity vulnerability in Envoyproxy Envoy, classified under NULL Pointer Dereference. CVSS score: 7.5/10. Published 2022-02-22.

How severe is CVE-2021-43824?

High severity. CVSS v3 base score is 7.5 out of 10.

Is CVE-2021-43824 known to be exploited?

2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

NULL pointer dereference in Envoyproxy Envoy

CVE-2021-43824

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.

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 >= 1.20.0, < 1.20.2, >= 1.19.0, < 1.19.3, < 1.18.6

Weakness classification (CWE)

CWE-476 — NULL Pointer Dereference

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-2021-43824?: CVE-2021-43824 is a high-severity vulnerability in Envoyproxy Envoy, classified under NULL Pointer Dereference. CVSS score: 7.5/10. Published 2022-02-22.
How severe is CVE-2021-43824?: High severity. CVSS v3 base score is 7.5 out of 10.
Is CVE-2021-43824 known to be exploited?: 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.