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.
https://kb.cert.org/vuls/id/605641/
https://github.com/Netflix/security-bulletins/blob/master/advisories/third-party/2019-002.md
https://seclists.org/bugtraq/2019/Aug/24
https://usn.ubuntu.com/4099-1/
http://seclists.org/fulldisclosure/2019/Aug/16
https://www.synology.com/security/advisory/Synology_SA_19_33
https://support.f5.com/csp/article/K02591030
https://seclists.org/bugtraq/2019/Aug/40
https://www.debian.org/security/2019/dsa-4505
https://security.netapp.com/advisory/ntap-20190823-0005/
https://security.netapp.com/advisory/ntap-20190823-0002/
http://lists.opensuse.org/opensuse-security-announce/2019-09/msg00035.html
http://lists.opensuse.org/opensuse-security-announce/2019-09/msg00032.html
http://lists.opensuse.org/opensuse-security-announce/2019-09/msg00031.html
https://kc.mcafee.com/corporate/index?page=content&id=SB10296
https://access.redhat.com/errata/RHSA-2019:2746
https://access.redhat.com/errata/RHSA-2019:2745
https://access.redhat.com/errata/RHSA-2019:2775
https://access.redhat.com/errata/RHSA-2019:2799
https://access.redhat.com/errata/RHSA-2019:2925
https://access.redhat.com/errata/RHSA-2019:2939
https://access.redhat.com/errata/RHSA-2019:2946
https://access.redhat.com/errata/RHSA-2019:2950
https://access.redhat.com/errata/RHSA-2019:2955
https://access.redhat.com/errata/RHSA-2019:2966
http://lists.opensuse.org/opensuse-security-announce/2019-10/msg00014.html
https://support.f5.com/csp/article/K02591030?utm_source=f5support&utm_medium=RSS
https://access.redhat.com/errata/RHSA-2019:3935
https://access.redhat.com/errata/RHSA-2019:3933
Source: MITRE
Published: 2019-08-13
Updated: 2022-08-05
Type: CWE-770
Base Score: 6.8
Vector: AV:N/AC:L/Au:S/C:N/I:N/A:C
Impact Score: 6.9
Exploitability Score: 8
Severity: MEDIUM
Base Score: 6.5
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Impact Score: 3.6
Exploitability Score: 2.8
Severity: MEDIUM