CVE-2024-27316: 
Apache HTTP Server vulnerability analysis and mitigation

CVE-2024-27316 is a vulnerability in Apache HTTP Server affecting versions 2.4.17 through 2.4.58. The vulnerability was discovered by Bartek Nowotarski and disclosed on February 22, 2024. The issue involves HTTP/2 incoming headers exceeding the limit being temporarily buffered in nghttp2 to generate an informative HTTP 413 response. If a client does not stop sending headers, this leads to memory exhaustion (Apache Security, CERT VU).

The vulnerability is related to the handling of HTTP/2 CONTINUATION frames in the Apache HTTP Server. When processing HTTP/2 headers that exceed the limit, the server temporarily buffers them in nghttp2 to generate an HTTP 413 response. However, if a client continues sending headers without setting the END_HEADERS flag, the server keeps accumulating data, leading to memory exhaustion. The vulnerability has been assigned a CVSS v3.1 base score of 7.5 (HIGH) with the vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (NVD).

The primary impact of this vulnerability is the potential for Denial of Service (DoS) attacks. An attacker can exploit this vulnerability by sending continuous streams of HTTP/2 CONTINUATION frames without the END_HEADERS flag set, causing the server to consume excessive memory resources until it crashes (CERT VU).

The vulnerability has been fixed in Apache HTTP Server version 2.4.59. Users running affected versions (2.4.17 through 2.4.58) are strongly recommended to upgrade to version 2.4.59 or later to address this security issue (Apache Security).