HTTP/2 incoming headers exceeding the limit are temporarily buffered in nghttp2 in order to generate an informative HTTP 413 response. If a client does not stop sending headers, this leads to memory exhaustion.

References

• https://nvd.nist.gov/vuln/detail/CVE-2024-27316
• https://httpd.apache.org/security/vulnerabilities_24.html
• https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/MIUBKSCJGPJ6M2U63V6BKFDF725ODLG7
• https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/QKKDVFWBKIHCC3WXNH3W75WWY4NW42OB
• https://security.netapp.com/advisory/ntap-20240415-0013
• https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/FO73U3SLBYFGIW2YKXOK7RI4D6DJSZ2B
• http://www.openwall.com/lists/oss-security/2024/04/03/16
• http://www.openwall.com/lists/oss-security/2024/04/04/4
• https://lists.debian.org/debian-lts-announce/2024/05/msg00013.html
• https://www.openwall.com/lists/oss-security/2024/04/03/16
• https://support.apple.com/kb/HT214119
• http://seclists.org/fulldisclosure/2024/Jul/18