CVE-2019-8460

Name: CVE-2019-8460
Creator: NVD / NIST
Published: 2019-08-26T20:15:10.03+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 2.19%

Last modified Jun 17, 2026

CVE-2019-8460 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. OpenBSD kernel version <= 6.5 can be forced to create long chains of TCP SACK holes that causes very expensive calls to tcp_sack_option() for every incoming SACK packet which can lead to a denial of service.. EPSS estimates a 2.19% chance of exploitation in the next 30 days.

Description

OpenBSD kernel version <= 6.5 can be forced to create long chains of TCP SACK holes that causes very expensive calls to tcp_sack_option() for every incoming SACK packet which can lead to a denial of service.

Metrics

CVSS 3.1

7.5/10

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

EPSS Probability

2.19%

80.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-1049

Affected Software

Vendor	Product	Versions
Openbsd	Openbsd	<= 6.5

References

https://ftp.openbsd.org/pub/OpenBSD/patches/6.5/common/006_tcpsack.patch.sigExploit, Vendor Advisory
https://github.com/openbsd/src/commit/ed8fdce754a5d8d14c09e989d8877707bd43906fPatch, Third Party Advisory
https://research.checkpoint.com/tcp-sack-security-issue-in-openbsd-cve-2019-8460/Exploit, Patch, Press/Media Coverage, Third Party Advisory
https://security.netapp.com/advisory/ntap-20190905-0001/Third Party Advisory
https://us-cert.cisa.gov/ics/advisories/icsa-19-253-03
https://ftp.openbsd.org/pub/OpenBSD/patches/6.5/common/006_tcpsack.patch.sigExploit, Vendor Advisory
https://github.com/openbsd/src/commit/ed8fdce754a5d8d14c09e989d8877707bd43906fPatch, Third Party Advisory
https://research.checkpoint.com/tcp-sack-security-issue-in-openbsd-cve-2019-8460/Exploit, Patch, Press/Media Coverage, Third Party Advisory
https://security.netapp.com/advisory/ntap-20190905-0001/Third Party Advisory
https://us-cert.cisa.gov/ics/advisories/icsa-19-253-03

Timeline

Published: Aug 26, 2019
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2019-8460?

How severe is CVE-2019-8460?

CVE-2019-8460 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 2.19% probability of exploitation in the next 30 days.

How do I fix CVE-2019-8460?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2019-8460?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST