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Status published
High
CVE-2021-43824
Null pointer dereference in envoy
Vulnerability Description
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.
Impact Analysis
Refer to official advisory for detailed impact metrics.
Remediation
Ensure systems are updated to the latest vendor-supplied patch levels.
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Credits & Attribution
No credits recorded in the NVD database.
References
More from envoyproxy
View All →CVE-2025-66220
Envoy’s TLS certificate matcher for `match_typed_subject_alt_names` may incorrectly treat certificates containing an embedded null byte
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CVE-2025-64763
Envoy forwards early CONNECT data in TCP proxy mode
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3.7
CVE-2025-64527
Envoy crashes when JWT authentication is configured with the remote JWKS fetching
Medium
6.5
CVE-2025-62504
Envoy Lua filter use-after-free when oversized rewritten response body causes crash
Medium
6.5
CVE-2025-62409
Envoy allows large requests and responses to cause TCP connection pool crash
Medium
6.6
Affected Vendor
envoyproxy
View all reports →Affected Software
envoy
Vulnerable Versions:
>= 1.20.0, < 1.20.2, >= 1.19.0, < 1.19.3, < 1.18.6, >= 1.21.0, < 1.21.1
Timeline
Official Publish:
February 22nd, 2022
Last Modified:
April 23rd, 2025
Added to House:
July 21st, 2026
CVSS Vectors
V3:
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H