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Fencer Intel
high 7.5

CVE-2019-8460 json

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() f…

published 7y ago modified 4mo ago also EUVD-2019-17850

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.3%
EPSS 2.3% chance of exploitation in 30 days, percentile 83%
public exploits
0
none known

Summary

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.

Patch / fix

Is CVE-2019-8460 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

cisa ICSA-19-253-03 updated cvss 7.5

ICSA-19-253-03_Siemens Industrial Products (Update P)

From CISA ICS and IT advisories (CSAF, https://github.com/cisagov/CSAF), a U.S. Government work; changed: reduced to products, statuses and remediations. CISA notification · csaf

Exploit prediction

2.25% chance of exploitation in the next 30 days, higher than 83% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • research.checkpoint.com https://research.checkpoint.com/tcp-sack-security-issue-in-openbsd-cve-2019-8460/ referenced PoC, tagged "exploit" by a source, unverified
  • ftp.openbsd.org https://ftp.openbsd.org/pub/OpenBSD/patches/6.5/common/006_tcpsack.patch.sig referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P

Affected products

  • n/a OpenBSD

Classification

Weakness
  • CWE-1049 Excessive Data Query Operations in a Large Data Table

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.