High severity · published Jun 25, 2026
CVE-2026-57589
sys/kern/sysv_sem.c in OpenBSD through 7.9 has a use-after-free allowing local privilege escalation to root
7.8
CVSS
0.2%
EPSS
No
On KEV
Description
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().
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 6% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
OP
OpenBSD · OpenBSD
through 7.9 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-57589
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-57589
Patch
https://github.com/openbsd/src/commit/1957873d2063db11dab780eca75b5e629d1e838d
Third Party Advisory
https://openai.com/index/patch-the-planet/
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