CVE-2019-9516
CWE-400Published: August 13, 2019· Updated: Jun 17, 2026
Official Description
Some HTTP/2 implementations are vulnerable to a header leak, potentially leading to a denial of service. The attacker sends a stream of headers with a 0-length header name and 0-length header value, optionally Huffman encoded into 1-byte or greater headers. Some implementations allocate memory for these headers and keep the allocation alive until the session dies. This can consume excess memory.
Technical Analysis
CVE-2019-9516 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.
Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
A successful exploit results in availability disruption (denial of service), with a CVSS base score of 6.5.
CVSS v3.1 Vector Breakdown
Affected Vendors & Products
Exploit & PoC Resources
Official Patches & Advisories
All References (74)
Quick Facts
Related CVEs (CWE-400)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2019-9516 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts