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CVE-2019-8460OpenBSD kernel version <= 6.5 can be forced to create long chains of TCP SACK holes that causes very expensive calls to tcp_sack_option()…
- 7.5HighCVSS base score
- 2.3%Exploitation in 30 daysEPSS · top 17% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
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.
Timeline
ID reserved
By checkpoint
- 6 months later
· 6 months later
Published
- 5 years later
· 5 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| NVDNVD · Modified | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 2.3% · top 17% of all CVEs (12 Nov 2026)
Loading the EPSS history…
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.
Affected products
OpenBSD
- affected All, including latest - 6.5
References
References5
- https://github.com/openbsd/src/commit/ed8fdce754a5d8d14c09e989d8877707bd43906f (opens in a new tab)x_refsource_MISCx_transferred
- https://ftp.openbsd.org/pub/OpenBSD/patches/6.5/common/006_tcpsack.patch.sig (opens in a new tab)x_refsource_MISCx_transferred
- https://security.netapp.com/advisory/ntap-20190905-0001/ (opens in a new tab)x_refsource_CONFIRMx_transferred
- https://research.checkpoint.com/tcp-sack-security-issue-in-openbsd-cve-2019-8460/ (opens in a new tab)x_refsource_MISCx_transferred
- https://us-cert.cisa.gov/ics/advisories/icsa-19-253-03 (opens in a new tab)x_refsource_MISCx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2019-17850 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2019-8460)Record last updated .