CVE-2020-11080 | Denial of service in nghttp2

In nghttp2 before version 1.41.0, the overly large HTTP/2 SETTINGS frame payload causes denial of service. The proof of concept attack involves a malicious client constructing a SETTINGS frame with a length of 14,400 bytes (2400 individual settings entries) over and over again. The attack causes the CPU to spike at 100%. nghttp2 v1.41.0 fixes this vulnerability. There is a workaround to this vulnerability. Implement nghttp2_on_frame_recv_callback callback, and if received frame is SETTINGS frame and the number of settings entries are large (e.g., > 32), then drop the connection.

Published: 2020-06-03 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2020-11080 is rated Moderate Risk (46.8/100): CVSS Low severity, with high exploitation likelihood (EPSS 5.32%, 92th percentile). EPSS ranks this CVE among the most likely to be exploited in the near term. 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-2020-11080

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 2026-06-20 5.36% 5.32% -0.04%
2 2026-06-15 1.25% 5.36% +4.11%
3 2026-05-09 — 1.25% —

Full EPSS history (33 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-11080

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
3.7 3.1 LOW
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L 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:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
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:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
 2.2 1.4 [email protected]
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]
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:N/I:N/A:P 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:P)
Partial availability impact.
 10.0 2.9 [email protected]

Weakness enumeration for CVE-2020-11080

OS Trackers for CVE-2020-11080

vendor priority summary link
alpine high CVE-2020-11080: 3 source package rows (nghttp2, nodejs, nodejs-current); 31 state rows across 17 repos (3.10-main, 3.11-main, 3.12-main, 3.17-community, 3.17-main, 3.18-community, 3.18-main, 3.19-community, 3.19-main, 3.20-community, 3.20-main, 3.21-community, 3.21-main, 3.22-community, 3.22-main, edge-community, edge-main); fixed 26, open 5. https://security.alpinelinux.org/vuln/CVE-2020-11080
debian not yet assigned CVE-2020-11080 not yet assigned priority: Debian including 2 source packages (nghttp2, nodejs), 10 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 10. https://security-tracker.debian.org/tracker/CVE-2020-11080
redhat high — https://access.redhat.com/security/cve/CVE-2020-11080
suse high CVE-2020-11080 severity important: SUSE including 456 source package names (0.21.0.3.2.10:libnghttp2-14-1.40.0-3.5.1, 0.38.1.5.8.40:libnghttp2-14-1.40.0-3.5.1, …), 948 product×package rows across 407 product lines (Container bci/bci-init, Container bci/dotnet-aspnet, … (407 product lines)): Fixed 798, Known Affected 135, Known Not Affected 15. https://www.suse.com/security/cve/CVE-2020-11080/
ubuntu medium CVE-2020-11080 medium priority: Ubuntu including 2 source packages (nghttp2, nodejs), 28 status rows across 16 suites (bionic, eoan, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, trusty, upstream, xenial): not-affected 17, ignored 5, released 3, needs-triage 2, DNE 1. https://ubuntu.com/security/CVE-2020-11080

Affected software / configurations for CVE-2020-11080

Vendor Product Version Raw CPE
nghttp2 nghttp2 < 1.41.0 cpe:2.3:a:nghttp2:nghttp2:*:*:*:*:*:*:*:*
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:*:*:*:*:*:*:*
opensuse leap 15.1 cpe:2.3:o:opensuse:leap:15.1:*:*:*:*:*:*:*
fedoraproject fedora 31 cpe:2.3:o:fedoraproject:fedora:31:*:*:*:*:*:*:*
fedoraproject fedora 33 cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
oracle banking_extensibility_workbench 14.3.0 cpe:2.3:a:oracle:banking_extensibility_workbench:14.3.0:*:*:*:*:*:*:*
oracle banking_extensibility_workbench 14.4.0 cpe:2.3:a:oracle:banking_extensibility_workbench:14.4.0:*:*:*:*:*:*:*
oracle blockchain_platform < 21.1.2 cpe:2.3:a:oracle:blockchain_platform:*:*:*:*:*:*:*:*
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:*:*:*:*:*:*:*
oracle graalvm 19.3.2 cpe:2.3:a:oracle:graalvm:19.3.2:*:*:*:enterprise:*:*:*
oracle graalvm 20.1.0 cpe:2.3:a:oracle:graalvm:20.1.0:*:*:*:enterprise:*:*:*
oracle mysql >= 7.3.0, <= 7.3.30 cpe:2.3:a:oracle:mysql:*:*:*:*:*:*:*:*
oracle mysql >= 7.4.0, <= 7.4.29 cpe:2.3:a:oracle:mysql:*:*:*:*:*:*:*:*
oracle mysql >= 7.5.0, <= 7.5.19 cpe:2.3:a:oracle:mysql:*:*:*:*:*:*:*:*
oracle mysql >= 7.6.0, <= 7.6.15 cpe:2.3:a:oracle:mysql:*:*:*:*:*:*:*:*
oracle mysql >= 8.0.0, <= 8.0.21 cpe:2.3:a:oracle:mysql:*:*:*:*:*:*:*:*
nodejs node.js >= 10.0.0, <= 10.12.0 cpe:2.3:a:nodejs:node.js:*:*:*:*:-:*:*:*
nodejs node.js >= 10.13.0, < 10.21.0 cpe:2.3:a:nodejs:node.js:*:*:*:*:lts:*:*:*
nodejs node.js >= 12.0.0, <= 12.12.0 cpe:2.3:a:nodejs:node.js:*:*:*:*:-:*:*:*
nodejs node.js >= 12.13.0, < 12.18.0 cpe:2.3:a:nodejs:node.js:*:*:*:*:lts:*:*:*
nodejs node.js >= 14.0.0, <= 14.4.0 cpe:2.3:a:nodejs:node.js:*:*:*:*:-:*:*:*

References for CVE-2020-11080

URL Tags
http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00024.html Mailing List Third Party Advisory
https://github.com/nghttp2/nghttp2/commit/336a98feb0d56b9ac54e12736b18785c27f75090 Patch Third Party Advisory
https://github.com/nghttp2/nghttp2/commit/f8da73bd042f810f34d19f9eae02b46d870af394 Patch Third Party Advisory
https://github.com/nghttp2/nghttp2/security/advisories/GHSA-q5wr-xfw9-q7xr Patch Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/10/msg00011.html Mailing List Third Party Advisory
https://lists.debian.org/debian-lts-announce/2023/10/msg00023.html
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4OOYAMJVLLCLXDTHW3V5UXNULZBBK4O6/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/AAC2AA36OTRHKSVM5OV7TTVB3CZIGEFL/
https://www.debian.org/security/2020/dsa-4696 Third Party Advisory
https://www.oracle.com//security-alerts/cpujul2021.html Not Applicable Third Party Advisory
https://www.oracle.com/security-alerts/cpuapr2022.html Patch Third Party Advisory
https://www.oracle.com/security-alerts/cpujan2021.html Third Party Advisory
https://www.oracle.com/security-alerts/cpujul2020.html Third Party Advisory
https://www.oracle.com/security-alerts/cpuoct2020.html Third Party Advisory
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