# What is CVE-2019-9513?

> CVE-2019-9513 is a high-severity flaw (CVSS 7.5) in Swiftnio from Apple, published on 13 August 2019. It is not on the list of flaws known to be exploited today. The latest forecast puts its chance of use in the next 30 days at 82%. If you run an affected version, plan in the vendor’s fix.

Canonical page: https://www.precursorintelligence.com/what-is/cve-2019-9513

## At a glance

- **Verdict:** Fix this soon. Not confirmed as exploited yet, but serious or likely enough that it should not wait for a quiet month.
- **Precursor Intelligence risk score:** 61 out of 100 (Medium); action: Plan remediation. Kept up to date as the evidence changes.
- **Severity:** High (CVSS 7.5 out of 10)
- **Known to be exploited:** No, not on the list of flaws known to be exploited today
- **Chance of use in the next 30 days:** 82% (latest exploit-likelihood forecast)
- **Published:** 13 August 2019
- **Record last updated:** 14 January 2025
- **Main product:** Swiftnio from Apple
- **Affected products:** 22

## What is CVE-2019-9513? In plain terms

It can be attacked from anywhere on the internet without logging in, and nobody has to click anything. If it works, the attacker can take it offline.

### The official description

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.

### What kind of flaw is it?

- CWE-400: Uncontrolled Resource Consumption

### How an attack on it works

- Where an attacker can be: Anywhere on the internet
- How hard it is to pull off: Easy: no special conditions
- Login needed first: No login needed
- Does someone have to click: No, nobody has to do anything
- What an attacker gets: Can take it offline

Severity vector: `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`

## Is CVE-2019-9513 being exploited? Not that we know of

It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 82%. That can change at any time, which is why we keep watching.

Exploit likelihood over the last 7 days: 82%, 82%, 82%, 82%, 82%, 82%, 82%.

### Timeline

- 13 August 2019: Published
- 14 January 2025: Record last updated
- 19 November 2025: Exploit likelihood jumped
- 22 November 2025: Exploit likelihood fell

### How Precursor Intelligence ranks it

CVE-2019-9513 scores **61 out of 100 (Medium)**, with the action "Plan remediation".

Every published flaw gets a risk score from 0 to 100, kept up to date as the evidence changes. Four things go into the score, from the one that counts most to the ones that count less:

- Evidence it is being exploited: biggest factor
- How severe it is: strong factor
- How widely exposed it is: smaller factor
- Threat activity around it: smaller factor

85 and above is Critical. Anything confirmed as exploited is always marked for an emergency patch, whatever its score. When this flaw matches software you track, it lands in your list with its score and the reasons behind it.

## Who is affected by CVE-2019-9513?

The published record lists 22 products. Versions are as published: "8.9.0 to before 8.16.1" means from 8.9.0 up to, but not including, 8.16.1.

- [Swiftnio](https://www.precursorintelligence.com/product/apple/swiftnio) by [Apple](https://www.precursorintelligence.com/vendors/apple) (Application): 1.0.0 to 1.4.0
- [Node.js](https://www.precursorintelligence.com/product/nodejs/node.js) by [Nodejs](https://www.precursorintelligence.com/vendors/nodejs) (Application): 8.0.0 to 8.8.1, 8.9.0 to before 8.16.1, 10.0.0 to 10.12.0, 10.13.0 to before 10.16.3, 12.0.0 to before 12.8.1
- [Traffic Server](https://www.precursorintelligence.com/product/apache/traffic_server) by [Apache](https://www.precursorintelligence.com/vendors/apache) (Application): 6.0.0 to 6.2.3, 7.0.0 to 7.1.6, 8.0.0 to 8.0.3
- [Web Gateway](https://www.precursorintelligence.com/product/mcafee/web_gateway) by [Mcafee](https://www.precursorintelligence.com/vendors/mcafee) (Application): 7.7.2.0 to before 7.7.2.24, 7.8.2.0 to before 7.8.2.13, 8.1.0 to before 8.2.0
- [Debian Linux](https://www.precursorintelligence.com/product/debian/debian_linux) by [Debian](https://www.precursorintelligence.com/vendors/debian) (Operating system): 9.0, 10.0
- [Enterprise Communications Broker](https://www.precursorintelligence.com/product/oracle/enterprise_communications_broker) by [Oracle](https://www.precursorintelligence.com/vendors/oracle) (Application): 3.1.0, 3.2.0
- [Fedora](https://www.precursorintelligence.com/product/fedoraproject/fedora) by [Fedoraproject](https://www.precursorintelligence.com/vendors/fedoraproject) (Operating system): 29, 30
- [Jboss Enterprise Application Platform](https://www.precursorintelligence.com/product/redhat/jboss_enterprise_application_platform) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Application): 7.2.0, 7.3.0
- [Leap](https://www.precursorintelligence.com/product/opensuse/leap) by [Opensuse](https://www.precursorintelligence.com/vendors/opensuse) (Operating system): 15.0, 15.1
- [Nginx](https://www.precursorintelligence.com/product/f5/nginx) by [F5](https://www.precursorintelligence.com/vendors/f5) (Application): 1.9.5 to before 1.16.1, 1.17.0 to 1.17.2
- [Diskstation Manager](https://www.precursorintelligence.com/product/synology/diskstation_manager) by [Synology](https://www.precursorintelligence.com/vendors/synology) (Operating system): 6.2
- [Enterprise Linux](https://www.precursorintelligence.com/product/redhat/enterprise_linux) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Operating system): 8.0
- [Graalvm](https://www.precursorintelligence.com/product/oracle/graalvm) by [Oracle](https://www.precursorintelligence.com/vendors/oracle) (Application): 19.2.0
- [Jboss Core Services](https://www.precursorintelligence.com/product/redhat/jboss_core_services) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Application): 1.0
- [Mac OS X](https://www.precursorintelligence.com/product/apple/mac_os_x) by [Apple](https://www.precursorintelligence.com/vendors/apple) (Operating system): 10.12 and later
- [Openshift Service Mesh](https://www.precursorintelligence.com/product/redhat/openshift_service_mesh) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Application): 1.0
- [Quay](https://www.precursorintelligence.com/product/redhat/quay) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Application): 3.0.0
- [Skynas](https://www.precursorintelligence.com/product/synology/skynas) by [Synology](https://www.precursorintelligence.com/vendors/synology) (Application): version not specified
- [Software Collections](https://www.precursorintelligence.com/product/redhat/software_collections) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Application): 1.0
- [Ubuntu Linux](https://www.precursorintelligence.com/product/canonical/ubuntu_linux) by [Canonical](https://www.precursorintelligence.com/vendors/canonical) (Operating system): 14.04 and later
- [Vs960hd](https://www.precursorintelligence.com/product/synology/vs960hd) by [Synology](https://www.precursorintelligence.com/vendors/synology) (Hardware): version not specified
- [Vs960hd Firmware](https://www.precursorintelligence.com/product/synology/vs960hd_firmware) by [Synology](https://www.precursorintelligence.com/vendors/synology) (Operating system): version not specified

## How do I fix CVE-2019-9513?

1. **Check whether you run it.** Compare your versions with the affected products above. Not sure what you run? Precursor Intelligence can work it out from your public website, or you can pick it from a list.
2. **Apply the vendor’s fix.** Install the latest update from the vendor. The references list where the vendor has published details.
3. **If you can’t patch today.** Follow any mitigation the vendor publishes, and limit who can reach the affected system from the internet until the update is in.
4. **Keep an eye on it.** Track the product and we tell you as soon as we spot this flaw on the list of exploited flaws, or a jump in its exploit likelihood.

### References

- [lists.opensuse.org](http://lists.opensuse.org/opensuse-security-announce/2019-09/msg00031.html) (Mailing list, Third-party advisory)
- [lists.opensuse.org](http://lists.opensuse.org/opensuse-security-announce/2019-09/msg00032.html) (Mailing list, Third-party advisory)
- [lists.opensuse.org](http://lists.opensuse.org/opensuse-security-announce/2019-09/msg00035.html) (Mailing list, Third-party advisory)
- [lists.opensuse.org](http://lists.opensuse.org/opensuse-security-announce/2019-10/msg00003.html) (Mailing list, Third-party advisory)
- [lists.opensuse.org](http://lists.opensuse.org/opensuse-security-announce/2019-10/msg00005.html) (Mailing list, Third-party advisory)
- [lists.opensuse.org](http://lists.opensuse.org/opensuse-security-announce/2019-10/msg00014.html) (Mailing list, Third-party advisory)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2019:2692) (Third-party advisory)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2019:2745) (Third-party advisory)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2019:2746) (Third-party advisory)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2019:2775) (Third-party advisory)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2019:2799) (Third-party advisory)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2019:2925) (Third-party advisory)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2019:2939) (Third-party advisory)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2019:2949) (Third-party advisory)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2019:2955) (Third-party advisory)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2019:2966) (Third-party advisory)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2019:3041) (Third-party advisory)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2019:3932) (Third-party advisory)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2019:3933) (Third-party advisory)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2019:3935) (Third-party advisory)
- [github.com](https://github.com/Netflix/security-bulletins/blob/master/advisories/third-party/2019-002.md) (Third-party advisory)
- [kb.cert.org](https://kb.cert.org/vuls/id/605641/) (Third-party advisory, Government resource)
- [kc.mcafee.com](https://kc.mcafee.com/corporate/index?page=content&id=SB10296) (Third-party advisory)
- [lists.fedoraproject.org](https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4ZQGHE3WTYLYAYJEIDJVF2FIGQTAYPMC/)
- [lists.fedoraproject.org](https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CMNFX5MNYRWWIMO4BTKYQCGUDMHO3AXP/)
- [lists.fedoraproject.org](https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JUBYAF6ED3O4XCHQ5C2HYENJLXYXZC4M/)
- [lists.fedoraproject.org](https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LZLUYPYY3RX4ZJDWZRJIKSULYRJ4PXW7/)
- [lists.fedoraproject.org](https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/POPAEC4FWL4UU4LDEGPY5NPALU24FFQD/)
- [lists.fedoraproject.org](https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TAZZEVTCN2B4WT6AIBJ7XGYJMBTORJU5/)
- [seclists.org](https://seclists.org/bugtraq/2019/Aug/40) (Mailing list, Third-party advisory)
- [seclists.org](https://seclists.org/bugtraq/2019/Sep/1) (Mailing list, Third-party advisory)
- [security.netapp.com](https://security.netapp.com/advisory/ntap-20190823-0002/) (Third-party advisory)
- [security.netapp.com](https://security.netapp.com/advisory/ntap-20190823-0005/) (Third-party advisory)
- [support.f5.com](https://support.f5.com/csp/article/K02591030) (Third-party advisory)
- [support.f5.com](https://support.f5.com/csp/article/K02591030?utm_source=f5support&amp%3Butm_medium=RSS)
- [usn.ubuntu.com](https://usn.ubuntu.com/4099-1/) (Third-party advisory)
- [debian.org](https://www.debian.org/security/2019/dsa-4505) (Third-party advisory)
- [debian.org](https://www.debian.org/security/2019/dsa-4511) (Third-party advisory)
- [debian.org](https://www.debian.org/security/2020/dsa-4669) (Third-party advisory)
- [oracle.com](https://www.oracle.com/security-alerts/cpujan2021.html) (Third-party advisory)
- [oracle.com](https://www.oracle.com/security-alerts/cpuoct2020.html) (Third-party advisory)
- [synology.com](https://www.synology.com/security/advisory/Synology_SA_19_33) (Third-party advisory)

## Questions

### What is CVE-2019-9513?

CVE-2019-9513 is a high-severity flaw in Swiftnio from Apple, published on 13 August 2019. It can be attacked from anywhere on the internet without logging in, and nobody has to click anything. If it works, the attacker can take it offline.

### How serious is CVE-2019-9513?

It scores 7.5 out of 10 on the CVSS severity scale, which is high. Our risk score for CVE-2019-9513 is 61 out of 100, which is Medium. Its action is "Plan remediation". Not confirmed as exploited yet, but serious or likely enough that it should not wait for a quiet month.

### Is CVE-2019-9513 being exploited?

It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 82%. That can change at any time, which is why we keep watching.

### Which versions does CVE-2019-9513 affect?

For Swiftnio from Apple: 1.0.0 to 1.4.0. The record lists 22 products in all, each with its versions, under "Who is affected" on this page.

### How do I fix CVE-2019-9513?

Install the update the vendor names in its advisory. If you can't patch today, follow the vendor's mitigation and limit who can reach the affected system from the internet.

## Does CVE-2019-9513 affect you?

Precursor Intelligence keeps checking for you:

- **Tell us what you run.** Pick your software from a list, or let us work it out from your website.
- **We match it to every flaw.** Over 400,000 published flaws, checked against your list.
- **Ranked by real-world risk.** Every flaw gets a 0 to 100 risk score, kept up to date, led by evidence criminals are using it.
- **Told as soon as we know.** An alert by email, in the app or by webhook to your own tools.

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