What’s Vulnerable › Vulnerabilities

CVE-2019-8460

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 2.3% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2019-08-26 · updated 2026-06-17
• Weakness: CWE-1049

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.

Affected products

• OpenBSD: through 6.5

References

• https://ftp.openbsd.org/pub/OpenBSD/patches/6.5/common/006_tcpsack.patch.sig
• https://github.com/openbsd/src/commit/ed8fdce754a5d8d14c09e989d8877707bd43906f
• https://research.checkpoint.com/tcp-sack-security-issue-in-openbsd-cve-2019-8460/
• https://security.netapp.com/advisory/ntap-20190905-0001/
• https://us-cert.cisa.gov/ics/advisories/icsa-19-253-03
• https://ftp.openbsd.org/pub/OpenBSD/patches/6.5/common/006_tcpsack.patch.sig
• https://github.com/openbsd/src/commit/ed8fdce754a5d8d14c09e989d8877707bd43906f
• https://research.checkpoint.com/tcp-sack-security-issue-in-openbsd-cve-2019-8460/
• https://security.netapp.com/advisory/ntap-20190905-0001/
• https://us-cert.cisa.gov/ics/advisories/icsa-19-253-03

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