High 7.5Published Aug 13, 2019

CVE-2019-9515Some HTTP/2 implementations are vulnerable to a settings flood, potentially leading to a denial of service.

Updated under an hour ago (Nov 2, 2026, 12:20 AM ET)

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It affects apple swiftnio and 21 other products. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Start free and add your stackFree account, 3 products Every CVE for apple swiftnio Exploited in the last 30 days

Some HTTP/2 implementations are vulnerable to a settings flood, potentially leading to a denial of service. The attacker sends a stream of SETTINGS frames to the peer. Since the RFC requires that the peer reply with one acknowledgement per SETTINGS frame, an empty SETTINGS frame is almost equivalent in behavior to a ping. Depending on how efficiently this data is queued, this can consume excess CPU, memory, or both.

CVSS: 7.5 HIGH (v3.1, NVD)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): CWE-400, CWE-770
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Not given
NVD analysis: Modified
Record last updated: Jun 16, 2026
First seen by InfoSec Signals: Nov 1, 2026

Affected products

Affected products

apple swiftnio apple:swiftnio	from 1.0.0 through 1.4.0	NVD
apache traffic_server apache:traffic_server	from 6.0.0 through 6.2.3; from 7.0.0 through 7.1.6; from 8.0.0 through 8.0.3	NVD
canonical ubuntu_linux canonical:ubuntu_linux	16.04; 18.04; 19.04	NVD
debian debian_linux debian:debian_linux	9.0; 10.0	NVD
synology skynas synology:skynas	all versions	NVD
synology diskstation_manager synology:diskstation_manager	6.2	NVD
synology vs960hd_firmware synology:vs960hd_firmware	all versions	NVD
fedoraproject fedora fedoraproject:fedora	29; 30	NVD
opensuse leap opensuse:leap	15.0; 15.1	NVD
redhat jboss_core_services redhat:jboss_core_services	1.0	NVD
1–10 of 22

References

References

http://lists.opensuse.org/opensuse-security-announce/2019-09/msg00031.html	mailing-list, third-party-advisory
http://lists.opensuse.org/opensuse-security-announce/2019-09/msg00032.html	mailing-list, third-party-advisory
http://seclists.org/fulldisclosure/2019/Aug/16	mailing-list, third-party-advisory
https://access.redhat.com/errata/RHSA-2019:2766	third-party-advisory
https://access.redhat.com/errata/RHSA-2019:2796	third-party-advisory
https://access.redhat.com/errata/RHSA-2019:2861	third-party-advisory
https://access.redhat.com/errata/RHSA-2019:2925	third-party-advisory
https://access.redhat.com/errata/RHSA-2019:2939	third-party-advisory
https://access.redhat.com/errata/RHSA-2019:2955	third-party-advisory
https://access.redhat.com/errata/RHSA-2019:3892	third-party-advisory
1–10 of 25

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.