When parsing HTTP/1.x header values, Envoy 1.9.0 and before does not reject embedded zero characters (NUL, ASCII 0x0). This allows remote attackers crafting header values containing embedded NUL characters to potentially bypass header matching rules, gaining access to unauthorized resources.

Related CVEs

CVE-2019-9900

Key Information

GHSA ID

GHSA-h9r7-c397-3wqr

Published

May 24, 2022 4:44 PM

Last Modified

April 4, 2024 12:06 AM

CVSS Score

7.5 /10

Primary Ecosystem

Unknown

Primary Package

Unknown

GitHub Reviewed

✗ No

Dataset

Last updated: September 29, 2025 6:31 AM

Data from GitHub Advisory Database. This information is provided for research and educational purposes.