CVE-2019-8460

Reference Links

• 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://www.cisa.gov/news-events/ics-advisories/icsa-19-253-03 (Advisory)

Parent vulnerabilities

(Appears in the following advisories)

• ICSA-19-253-03

Frequently Asked Questions

• What is CVE-2019-8460?

  CVE-2019-8460 is a vulnerability in the OpenBSD kernel version <= 6.5 that allows an attacker to force the creation of long chains of TCP SACK holes, leading to a denial of service.

• How severe is CVE-2019-8460?

  CVE-2019-8460 has a severity rating of 7.5 (high).

• Which version of OpenBSD is affected by CVE-2019-8460?

  OpenBSD versions up to and including 6.5 are affected by CVE-2019-8460.

• How can the CVE-2019-8460 vulnerability be exploited?

  An attacker can exploit the CVE-2019-8460 vulnerability by forcing the OpenBSD kernel to create long chains of TCP SACK holes, causing expensive calls to tcp_sack_option() for every incoming SACK packet.

• What is the recommended fix for CVE-2019-8460?

  Applying the patch provided by OpenBSD is recommended to fix the CVE-2019-8460 vulnerability. The patch can be downloaded from the official OpenBSD website.