CVE-2019-9513 | Some HTTP/2 implementations are vulnerable to resource loops, potentially leading to a denial of service

Some HTTP/2 implementations are vulnerable to resource loops, potentially leading to a denial of service. The attacker creates multiple request streams and continually shuffles the priority of the streams in a way that causes substantial churn to the priority tree. This can consume excess CPU.

Published: 2019-08-13 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2019-9513 is rated High Risk (69.9/100): CVSS High severity, with high exploitation likelihood (EPSS 82.57%, 100th percentile). EPSS ranks this CVE among the most likely to be exploited in the near term. EPSS rose +75.98% over the last day, indicating growing attacker interest. High exploitation likelihood—assess exposure and prioritize remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2019-9513

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 6.59% 82.57% +75.98%
2 2026-05-29 6.71% 6.59% -0.12%
3 2026-03-21 — 6.71% —

Full EPSS history (61 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2019-9513

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]
7.5 3.0 HIGH
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]
7.8 2.0 HIGH
AV:N/AC:L/Au:N/C:N/I:N/A:C Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:C)
Complete availability impact.
 10.0 6.9 [email protected]

Weakness enumeration for CVE-2019-9513

OS Trackers for CVE-2019-9513

vendor priority summary link
alpine — CVE-2019-9513: 3 source package rows (nghttp2, nginx, nodejs); 30 state rows across 10 repos (3.10-main, 3.11-main, 3.12-main, 3.17-main, 3.18-main, 3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-main); fixed 30, open 0. https://security.alpinelinux.org/vuln/CVE-2019-9513
debian not yet assigned CVE-2019-9513 not yet assigned priority: Debian including 3 source packages (nghttp2, nginx, nodejs), 15 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 15. https://security-tracker.debian.org/tracker/CVE-2019-9513
redhat high — https://access.redhat.com/security/cve/CVE-2019-9513
suse low CVE-2019-9513 severity low: SUSE including 173 source package names (0.1.0:libnghttp2-14-1.40.0-3.4.1, 0.1.75:libnghttp2-14-1.40.0-3.4.1, …), 434 product×package rows across 138 product lines (Container caasp/v4/389-ds, Container caasp/v4/busybox, … (138 product lines)): Fixed 271, Known Not Affected 163. https://www.suse.com/security/cve/CVE-2019-9513/
ubuntu medium CVE-2019-9513 medium priority: Ubuntu including 3 source packages (nghttp2, nginx, nodejs), 45 status rows across 16 suites (bionic, cosmic, disco, eoan, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, trusty, upstream, xenial): not-affected 16, released 16, ignored 10, needs-triage 2, DNE 1. https://ubuntu.com/security/CVE-2019-9513

Affected software / configurations for CVE-2019-9513

Vendor Product Version Raw CPE
apple swiftnio >= 1.0.0, <= 1.4.0 cpe:2.3:a:apple:swiftnio:*:*:*:*:*:*:*:*
apache traffic_server >= 6.0.0, <= 6.2.3 cpe:2.3:a:apache:traffic_server:*:*:*:*:*:*:*:*
apache traffic_server >= 7.0.0, <= 7.1.6 cpe:2.3:a:apache:traffic_server:*:*:*:*:*:*:*:*
apache traffic_server >= 8.0.0, <= 8.0.3 cpe:2.3:a:apache:traffic_server:*:*:*:*:*:*:*:*
canonical ubuntu_linux 16.04 cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:*
canonical ubuntu_linux 18.04 cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:*
canonical ubuntu_linux 19.04 cpe:2.3:o:canonical:ubuntu_linux:19.04:*:*:*:*:*:*:*
debian debian_linux 9.0 cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
debian debian_linux 10.0 cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
fedoraproject fedora 30 cpe:2.3:o:fedoraproject:fedora:30:*:*:*:*:*:*:*
synology skynas — cpe:2.3:a:synology:skynas:-:*:*:*:*:*:*:*
synology diskstation_manager 6.2 cpe:2.3:o:synology:diskstation_manager:6.2:*:*:*:*:*:*:*
synology vs960hd_firmware — cpe:2.3:o:synology:vs960hd_firmware:-:*:*:*:*:*:*:*
fedoraproject fedora 29 cpe:2.3:o:fedoraproject:fedora:29:*:*:*:*:*:*:*
opensuse leap 15.0 cpe:2.3:o:opensuse:leap:15.0:*:*:*:*:*:*:*
opensuse leap 15.1 cpe:2.3:o:opensuse:leap:15.1:*:*:*:*:*:*:*
redhat jboss_core_services 1.0 cpe:2.3:a:redhat:jboss_core_services:1.0:*:*:*:*:*:*:*
redhat jboss_enterprise_application_platform 7.2.0 cpe:2.3:a:redhat:jboss_enterprise_application_platform:7.2.0:*:*:*:*:*:*:*
redhat jboss_enterprise_application_platform 7.3.0 cpe:2.3:a:redhat:jboss_enterprise_application_platform:7.3.0:*:*:*:*:*:*:*
redhat openshift_service_mesh 1.0 cpe:2.3:a:redhat:openshift_service_mesh:1.0:*:*:*:*:*:*:*
redhat quay 3.0.0 cpe:2.3:a:redhat:quay:3.0.0:*:*:*:*:*:*:*
redhat software_collections 1.0 cpe:2.3:a:redhat:software_collections:1.0:*:*:*:*:*:*:*
redhat enterprise_linux 8.0 cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*
oracle graalvm 19.2.0 cpe:2.3:a:oracle:graalvm:19.2.0:*:*:*:enterprise:*:*:*
mcafee web_gateway >= 7.7.2.0, < 7.7.2.24 cpe:2.3:a:mcafee:web_gateway:*:*:*:*:*:*:*:*
mcafee web_gateway >= 7.8.2.0, < 7.8.2.13 cpe:2.3:a:mcafee:web_gateway:*:*:*:*:*:*:*:*
mcafee web_gateway >= 8.1.0, < 8.2.0 cpe:2.3:a:mcafee:web_gateway:*:*:*:*:*:*:*:*
f5 nginx >= 1.9.5, < 1.16.1 cpe:2.3:a:f5:nginx:*:*:*:*:*:*:*:*
f5 nginx >= 1.17.0, <= 1.17.2 cpe:2.3:a:f5:nginx:*:*:*:*:*:*:*:*
oracle enterprise_communications_broker 3.1.0 cpe:2.3:a:oracle:enterprise_communications_broker:3.1.0:*:*:*:*:*:*:*
oracle enterprise_communications_broker 3.2.0 cpe:2.3:a:oracle:enterprise_communications_broker:3.2.0:*:*:*:*:*:*:*
nodejs node.js >= 8.0.0, <= 8.8.1 cpe:2.3:a:nodejs:node.js:*:*:*:*:-:*:*:*
nodejs node.js >= 8.9.0, < 8.16.1 cpe:2.3:a:nodejs:node.js:*:*:*:*:lts:*:*:*
nodejs node.js >= 10.0.0, <= 10.12.0 cpe:2.3:a:nodejs:node.js:*:*:*:*:-:*:*:*
nodejs node.js >= 10.13.0, < 10.16.3 cpe:2.3:a:nodejs:node.js:*:*:*:*:lts:*:*:*
nodejs node.js >= 12.0.0, < 12.8.1 cpe:2.3:a:nodejs:node.js:*:*:*:*:-:*:*:*

References for CVE-2019-9513

URL Tags
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://lists.opensuse.org/opensuse-security-announce/2019-09/msg00035.html Mailing List Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2019-10/msg00003.html Mailing List Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2019-10/msg00005.html Mailing List Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2019-10/msg00014.html Mailing List Third Party Advisory
https://access.redhat.com/errata/RHSA-2019:2692 Third Party Advisory
https://access.redhat.com/errata/RHSA-2019:2745 Third Party Advisory
https://access.redhat.com/errata/RHSA-2019:2746 Third Party Advisory
https://access.redhat.com/errata/RHSA-2019:2775 Third Party Advisory
https://access.redhat.com/errata/RHSA-2019:2799 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-2019:2949 Third Party Advisory
https://access.redhat.com/errata/RHSA-2019:2955 Third Party Advisory
https://access.redhat.com/errata/RHSA-2019:2966 Third Party Advisory
https://access.redhat.com/errata/RHSA-2019:3041 Third Party Advisory
https://access.redhat.com/errata/RHSA-2019:3932 Third Party Advisory
https://access.redhat.com/errata/RHSA-2019:3933 Third Party Advisory
https://access.redhat.com/errata/RHSA-2019:3935 Third Party Advisory
https://github.com/Netflix/security-bulletins/blob/master/advisories/third-party/2019-002.md Third Party Advisory
https://kb.cert.org/vuls/id/605641/ Third Party Advisory US Government Resource
https://kc.mcafee.com/corporate/index?page=content&id=SB10296 Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4ZQGHE3WTYLYAYJEIDJVF2FIGQTAYPMC/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CMNFX5MNYRWWIMO4BTKYQCGUDMHO3AXP/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JUBYAF6ED3O4XCHQ5C2HYENJLXYXZC4M/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LZLUYPYY3RX4ZJDWZRJIKSULYRJ4PXW7/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/POPAEC4FWL4UU4LDEGPY5NPALU24FFQD/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TAZZEVTCN2B4WT6AIBJ7XGYJMBTORJU5/
https://seclists.org/bugtraq/2019/Aug/40 Mailing List Third Party Advisory
https://seclists.org/bugtraq/2019/Sep/1 Mailing List Third Party Advisory
https://security.netapp.com/advisory/ntap-20190823-0002/ Third Party Advisory
https://security.netapp.com/advisory/ntap-20190823-0005/ Third Party Advisory
https://support.f5.com/csp/article/K02591030 Third Party Advisory
https://support.f5.com/csp/article/K02591030?utm_source=f5support&amp%3Butm_medium=RSS
https://usn.ubuntu.com/4099-1/ Third Party Advisory
https://www.debian.org/security/2019/dsa-4505 Third Party Advisory
https://www.debian.org/security/2019/dsa-4511 Third Party Advisory
https://www.debian.org/security/2020/dsa-4669 Third Party Advisory
https://www.oracle.com/security-alerts/cpujan2021.html Third Party Advisory
https://www.oracle.com/security-alerts/cpuoct2020.html Third Party Advisory
https://www.synology.com/security/advisory/Synology_SA_19_33 Third Party Advisory
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