Resource exhaustion in Apache HTTP Server
CVE-2019-9517
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.
Vulnerability class: DoS (Denial of Service)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.279 (98.1th percentile), scored .
Moderate probability of exploitation in the next 30 days — watch for active exploitation reports. 98th percentile — 98.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.279 · newest: 0.279 · change: 0.000
Affected products
Weakness classification (CWE)
Public proof-of-concept exploits
References
- kb.cert.org/vuls/id/605641/ (US Government Resource, Third Party Advisory, third-party-advisory)
- github.com/Netflix/security-bulletins/blob/master/advisories/third-party/2019-0… (Third Party Advisory)
- lists.apache.org/thread.html/4610762456644181b267c846423b3a990bd4aaea1886ecc7d5… (mailing-list)
- lists.apache.org/thread.html/56c2e7cc9deb1c12a843d0dc251ea7fd3e7e80293cde02fcd6… (mailing-list)
- www.openwall.com/lists/oss-security/2019/08/15/7 (mailing-list, Mailing List, Third Party Advisory)
- lists.apache.org/thread.html/ec97fdfc1a859266e56fef084353a34e0a0b08901b3c1aa317… (mailing-list)
- lists.apache.org/thread.html/d89f999e26dfb1d50f247ead1fe8538014eb412b2dbe5be4b1… (mailing-list)
- www.synology.com/security/advisory/Synology_SA_19_33 (Third Party Advisory)
- support.f5.com/csp/article/K02591030 (Third Party Advisory)
- security.netapp.com/advisory/ntap-20190823-0005/ (Third Party Advisory)
Frequently asked questions
- What is CVE-2019-9517?
- CVE-2019-9517 is a high-severity vulnerability in Apache HTTP Server, classified under Uncontrolled Resource Consumption. CVSS score: 7.5/10. Published 2019-08-13.
- How severe is CVE-2019-9517?
- High severity. CVSS v3 base score is 7.5 out of 10.
- Is CVE-2019-9517 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.