Public proof of conceptFix available

CVE-2019-9511

Q: Is CVE-2019-9511 actively exploited?

Active exploitation of CVE-2019-9511 has not been confirmed. Its EPSS score was 59.5% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2019-9511?

CVE-2019-9511 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

A public proof of concept exists; no exploitation attested.

Published2019-08-13
Fixed in12.8.1 · 10.16.3 · 8.16.1
WeaknessCWE-400 · CWE-770

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

Some HTTP/2 implementations are vulnerable to window size manipulation and stream prioritization manipulation, potentially leading to a denial of service. The attacker requests a large amount of data from a specified resource over multiple streams. They manipulate window size and stream priority to force the server to queue the data in 1-byte chunks. Depending on how efficiently this data is queued, this can consume excess CPU, memory, or both.

Timeline

dates in UTC

2019-08-1321:15CVE publishedNVD
2026-10-2319:23First public proof of conceptPoC-in-GitHub
2026-10-2319:23EPSS crossed 10 %FIRST EPSS

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2019-9511?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2019-9511?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Node.js

Branch	Affected	Fixed in	Source
12.x	≥ 12.0.0, < 12.8.1	12.8.1	NVD
10.x	≥ 10.13.0, < 10.16.3	10.16.3	NVD
8.x	≥ 8.9.0, < 8.16.1	8.16.1	NVD
8.x	≥ 8.0.0, ≤ 8.8.1	no fix published	NVD
10.x	≥ 10.0.0, ≤ 10.12.0	no fix published	NVD

Apache traffic server

Branch	Affected	Fixed in	Source
6.x	≥ 6.0.0, ≤ 6.2.3	no fix published	NVD
7.x	≥ 7.0.0, ≤ 7.1.6	no fix published	NVD
8.0	≥ 8.0.0, ≤ 8.0.3	no fix published	NVD

Canonical ubuntu linux

Branch	Affected	Fixed in	Source
16.4	= 16.04	no fix published	NVD
18.4	= 18.04	no fix published	NVD
19.4	= 19.04	no fix published	NVD

17 more products in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

nginxAlmaLinux:8all versions · fixed in 1:1.14.1-9.module_el8.3.0+2165+af250afe.almaand 7 other packages
nginxAlmaLinux:8all versions · fixed in 1:1.14.1-9.module_el8.4.0+2221+af250afe.almaand 5 other packages
nginxAlmaLinux:8all versions · fixed in 1:1.14.1-9.module_el8.5.0+34+dc1cfba5.almaand 5 other packages
nodejs-nodemonAlmaLinux:8all versions · fixed in 1.18.3-1.module_el8.3.0+2023+d2377ea3
nodejs-nodemonAlmaLinux:8all versions · fixed in 1.18.3-1.module_el8.3.0+2047+b07ac28e
nodejs-packagingAlmaLinux:8all versions · fixed in 17-3.module_el8.3.0+2023+d2377ea3
nodejs-packagingAlmaLinux:8all versions · fixed in 17-3.module_el8.4.0+2224+b07ac28e
nodejs-packagingAlmaLinux:8all versions · fixed in 17-3.module_el8.4.0+2521+c668cc9f

Full record on NVD

Fix

Update Node.js to 12.8.1 · 10.16.3 · 8.16.1

Advisories and patches

www.oracle.comPatch

Detection

read 2026-10-23 19:23 UTC

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: 2 repositories, unverifiedflyniu666/ingress-nginx-0.21-1.19.5harley-ghostie/CVE-2019-9511_Priority-Churn-Data-Dribble

Sources

NVDCVSS 3.17.5read 2026-10-23
CNACVSS 3.07.5read 2026-10-23
NVDCVSS 2.07.8read 2026-10-23
CNAweakness (CWE)CWE-400read 2026-10-23
NVDweakness (CWE)CWE-770read 2026-10-23
FIRST EPSSEPSS score59.5 %read 2026-10-23
PoC-in-GitHubproof of concept2read 2026-10-23
OSVaffected packages—

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published: 2019-08-13
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2019-9511?

Is CVE-2019-9511 actively exploited?

Active exploitation of CVE-2019-9511 has not been confirmed. Its EPSS score was 59.5% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2019-9511?

CVE-2019-9511 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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