Resource exhaustion in envoy - #VU135119
Published: June 24, 2026
Vulnerability identifier: #VU135119
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: N/A
CWE-ID: CWE-400
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 improper resource management in the HTTP/3 QPACK decoder when processing blocked QPACK header blocks in HEADERS frames. A remote attacker can send a syntactically valid HEADERS frame that remains blocked on dynamic table updates to cause a denial of service.
Exploitation requires HTTP/3 to be enabled, support for the QPACK dynamic table, and a non-zero blocked-stream setting.
Remediation
Install security update from vendor's website.