The mod_http2 module in the Apache HTTP Server 2.4.17 through 2.4.23, when the Protocols configuration includes h2 or h2c, does not restrict request-header length, which allows remote attackers to cause a denial of service (memory consumption) via crafted CONTINUATION frames in an HTTP/2 request.
This vulnerability carries a HIGH severity rating with a CVSS v3.1 score of 7.5, indicating it can be exploited remotely over the network with relatively low complexity without requiring user interaction and does not require pre-existing privileges . The vulnerability impacts and availability (service disruption) for affected systems. Impacting 1 product from apache organizations running these solutions should prioritize assessment and patching.
First disclosed in 2016, this vulnerability was reported during a period defined by widespread IoT adoption challenges, mobile security concerns, and the emergence of advanced persistent threat (APT) techniques. Contemporary mitigation strategies focused on secure development practices and third-party component vetting.
2016-12-05T19:59:00.250
2025-04-12T10:46:40.837
Deferred
CVSSv3.0: 7.5 (HIGH)
AV:N/AC:L/Au:N/C:N/I:N/A:P
10.0
2.9
| Type | Vendor | Product | Version/Range | Vulnerable? |
|---|---|---|---|---|
| Application | apache | http_server | 2.4.17 | Yes |
| Application | apache | http_server | 2.4.18 | Yes |
| Application | apache | http_server | 2.4.19 | Yes |
| Application | apache | http_server | 2.4.20 | Yes |
| Application | apache | http_server | 2.4.21 | Yes |
| Application | apache | http_server | 2.4.22 | Yes |
| Application | apache | http_server | 2.4.23 | Yes |
SecUtils normalizes and enriches National Vulnerability Database (NVD) records by standardizing vendor and product identifiers, aggregating vulnerability metadata from both NVD and MITRE sources, and providing structured context for security teams. For apache's affected products, we extract Common Platform Enumeration (CPE) data, Common Weakness Enumeration (CWE) classifications, CVSS severity metrics, and reference data to enable rapid vulnerability prioritization and asset correlation. This record contains no exploit code, proof-of-concept instructions, or attack methodologies—only defensive intelligence necessary for patch management, risk assessment, and security operations.