Use After Free in OpenBSD
CVE-2026-57589
sys/kern/sysv_sem.c in OpenBSD through 7.9 has a use-after-free allowing local privilege escalation to root. This is a context switch use-after-free after tsleep in sys_semget().
Vulnerability class: Use-After-Free
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.4 (High). Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.002 (5.6th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 6th percentile — 5.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: 0.000
Affected products
- OpenBSD — versions 0
Weakness classification (CWE)
References
- github.com/openbsd/src/commit/1957873d2063db11dab780eca75b5e629d1e838d (Patch)
- openai.com/index/patch-the-planet/ (Third Party Advisory)
Frequently asked questions
- What is CVE-2026-57589?
- CVE-2026-57589 is a high-severity vulnerability in OpenBSD, classified under Use After Free. CVSS score: 7.4/10. Published 2026-06-25.
- How severe is CVE-2026-57589?
- High severity. CVSS v3 base score is 7.4 out of 10.