NULL pointer dereference in envoy - CVE-2026-47221
Published: June 24, 2026
Vulnerability identifier: #VU135115
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-47221
CWE-ID: CWE-476
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Cloud Native Computing Foundation
Affected software:
envoy
envoy
Detailed vulnerability description
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to a null pointer dereference in the router filter when handling HTTP 303 internal redirects for body-less non-GET/HEAD requests. A remote attacker can send a specially crafted request to cause a denial of service.
Exploitation requires a route configured with an internal redirect policy that includes 303 in redirect_response_codes, and an upstream response with HTTP 303.
How to mitigate CVE-2026-47221
Install security update from vendor's website.