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.
Conclusion & alert: CVE-2019-8460 is rated High Exploit Risk (69.7/100): CVSS High severity, with medium exploitation likelihood (EPSS 0.69%). Core evidence: 2 public exploit reference(s) are indexed (Exploit-DB). Mandatory action: Public exploits are available—assess exposure, apply mitigations, and prioritize patching.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
| EDB-ID | Source | Kind | Published | Link |
|---|---|---|---|---|
| — | nvd_ref | exploit_tag | Exploit-DB ↗ | |
| — | nvd_ref | exploit_tag | Exploit-DB ↗ |
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2025-11-21 | 0.80% | 0.69% | -0.12% |
| 2 | 2025-11-18 | 0.69% | 0.80% | +0.12% |
| 3 | 2025-03-30 | — | 0.69% | — |
Full EPSS history (12 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 7.5 | 3.1 | HIGH |
|
3.9 | 3.6 | [email protected] |
| 5.0 | 2.0 | MEDIUM |
|
10.0 | 2.9 | [email protected] |
| URL | Tags |
|---|---|
| https://ftp.openbsd.org/pub/OpenBSD/patches/6.5/common/006_tcpsack.patch.sig | Exploit Vendor Advisory |
| https://github.com/openbsd/src/commit/ed8fdce754a5d8d14c09e989d8877707bd43906f | Patch 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 |