Some HTTP/2 implementations are vulnerable to unconstrained interal data buffering, potentially leading to a denial of service

Description

Some HTTP/2 implementations are vulnerable to unconstrained interal data buffering, potentially leading to a denial of service. The attacker opens the HTTP/2 window so the peer can send without constraint; however, they leave the TCP window closed so the peer cannot actually write (many of) the bytes on the wire. The attacker then sends a stream of requests for a large response object. Depending on how the servers queue the responses, this can consume excess memory, CPU, or both.

Scores

EPSS (exploitation in 30 days)

27.0% · top 1.9% of all CVEs (6 Nov 2026)

The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.

Weakness

• CWE-400 Uncontrolled Resource Consumption (opens in a new tab)All about CWE-400 and its CVEs
• CWE-770 (opens in a new tab)All about CWE-770 and its CVEs

Affected products

• n/a

  • affected n/a

References (47)

• VU#605641 (opens in a new tab)third-party-advisoryx_refsource_CERT-VNx_transferred
• https://github.com/Netflix/security-bulletins/blob/master/advisories/third-party/2019-002.md (opens in a new tab)x_refsource_MISCx_transferred
• [httpd-announce] 20190814 CVE-2019-9517: mod_http2, DoS attack by exhausting h2 workers (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
• [httpd-cvs] 20190815 svn commit: r1048743 [4/4] - in /websites/staging/httpd/trunk/content: ./ security/vulnerabilities-httpd.xml security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabilities_24.html (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
• [oss-security] 20190814 CVE-2019-9517: mod_http2, DoS attack by exhausting h2 workers (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
• [httpd-dev] 20190817 CVE-2019-10097 vs. CHANGEs entry (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
• [httpd-dev] 20190817 Re: CVE-2019-10097 vs. CHANGEs entry (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
• https://www.synology.com/security/advisory/Synology_SA_19_33 (opens in a new tab)x_refsource_CONFIRMx_transferred
• https://support.f5.com/csp/article/K02591030 (opens in a new tab)x_refsource_CONFIRMx_transferred
• https://security.netapp.com/advisory/ntap-20190823-0005/ (opens in a new tab)x_refsource_CONFIRMx_transferred
• https://security.netapp.com/advisory/ntap-20190823-0003/ (opens in a new tab)x_refsource_CONFIRMx_transferred
• FEDORA-2019-5a6a7bc12c (opens in a new tab)vendor-advisoryx_refsource_FEDORAx_transferred
• FEDORA-2019-6a2980de56 (opens in a new tab)vendor-advisoryx_refsource_FEDORAx_transferred
• DSA-4509 (opens in a new tab)vendor-advisoryx_refsource_DEBIANx_transferred
• 20190826 [SECURITY] [DSA 4509-1] apache2 security update (opens in a new tab)mailing-listx_refsource_BUGTRAQx_transferred
• USN-4113-1 (opens in a new tab)vendor-advisoryx_refsource_UBUNTUx_transferred
• FEDORA-2019-4427fd65be (opens in a new tab)vendor-advisoryx_refsource_FEDORAx_transferred
• FEDORA-2019-63ba15cc83 (opens in a new tab)vendor-advisoryx_refsource_FEDORAx_transferred
• openSUSE-SU-2019:2051 (opens in a new tab)vendor-advisoryx_refsource_SUSEx_transferred
• https://security.netapp.com/advisory/ntap-20190905-0003/ (opens in a new tab)x_refsource_CONFIRMx_transferred
• GLSA-201909-04 (opens in a new tab)vendor-advisoryx_refsource_GENTOOx_transferred
• openSUSE-SU-2019:2114 (opens in a new tab)vendor-advisoryx_refsource_SUSEx_transferred
• openSUSE-SU-2019:2115 (opens in a new tab)vendor-advisoryx_refsource_SUSEx_transferred
• https://kc.mcafee.com/corporate/index?page=content&id=SB10296 (opens in a new tab)x_refsource_CONFIRMx_transferred
• RHSA-2019:2893 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
• RHSA-2019:2925 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
• RHSA-2019:2939 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
• RHSA-2019:2946 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
• RHSA-2019:2950 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
• RHSA-2019:2949 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
• RHSA-2019:2955 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
• https://support.f5.com/csp/article/K02591030?utm_source=f5support&amp%3Butm_medium=RSS (opens in a new tab)x_refsource_CONFIRMx_transferred
• https://www.oracle.com/technetwork/security-advisory/cpuoct2019-5072832.html (opens in a new tab)x_refsource_MISCx_transferred
• RHSA-2019:3933 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
• RHSA-2019:3935 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
• RHSA-2019:3932 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
• [httpd-cvs] 20200401 svn commit: r1058586 [4/4] - in /websites/staging/httpd/trunk/content: ./ security/vulnerabilities-httpd.xml security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabilities_24.html (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
• [httpd-cvs] 20200401 svn commit: r1058587 [4/4] - in /websites/staging/httpd/trunk/content: ./ security/vulnerabilities-httpd.xml security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabilities_24.html (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
• https://www.oracle.com/security-alerts/cpuapr2020.html (opens in a new tab)x_refsource_MISCx_transferred
• [httpd-cvs] 20210330 svn commit: r1073139 [1/13] - in /websites/staging/httpd/trunk/content: ./ security/json/ (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
• [httpd-cvs] 20210330 svn commit: r1073143 [3/3] - in /websites/staging/httpd/trunk/content: ./ security/ (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
• [httpd-cvs] 20210330 svn commit: r1073140 [4/4] - in /websites/staging/httpd/trunk/content: ./ security/cvejsontohtml.py security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabilities_24.html (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
• [httpd-cvs] 20210330 svn commit: r1073139 [12/13] - in /websites/staging/httpd/trunk/content: ./ security/json/ (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
• [httpd-cvs] 20210330 svn commit: r1888194 [12/13] - /httpd/site/trunk/content/security/json/ (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
• [httpd-cvs] 20210330 svn commit: r1073149 [1/13] - in /websites/staging/httpd/trunk/content: ./ security/ security/json/ (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
• [httpd-cvs] 20210330 svn commit: r1073149 [13/13] - in /websites/staging/httpd/trunk/content: ./ security/ security/json/ (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
• [httpd-cvs] 20210606 svn commit: r1075470 [4/4] - in /websites/staging/httpd/trunk/content: ./ security/json/CVE-2020-13938.json security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabilities_24.html (opens in a new tab)mailing-listx_refsource_MLISTx_transferred

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2019-9517](https://trackcve.app/badge/CVE-2019-9517.svg)](https://trackcve.app/cve/CVE-2019-9517)

Record last updated 4 Aug 2024, 21:54 UTC.