OpenBSD up to 7.9 sys/kern/sysv_sem.c sys_semget use after free

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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7.1$0-$5k4.22-

Summaryinfo

A vulnerability has been found in OpenBSD up to 7.9 and classified as critical. Affected by this vulnerability is the function sys_semget of the file sys/kern/sysv_sem.c. Performing a manipulation results in use after free. This vulnerability was named CVE-2026-57589. The attack needs to be approached locally. There is no available exploit. It is suggested to install a patch to address this issue.

Detailsinfo

A vulnerability, which was classified as critical, was found in OpenBSD up to 7.9. This affects the function sys_semget of the file sys/kern/sysv_sem.c. The manipulation with an unknown input leads to a use after free vulnerability. CWE is classifying the issue as CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

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().

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2026-57589 since 06/25/2026. The exploitability is told to be difficult. An attack has to be approached locally. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 06/25/2026).

Applying the patch 1957873d2063db11dab780eca75b5e629d1e838d is able to eliminate this problem. The bugfix is ready for download at github.com.

The vulnerability is also documented in the vulnerability database at CERT Bund (WID-SEC-2026-2066). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Affected

  • OpenBSD OpenBSD

Productinfo

Type

Name

Version

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.2
VulDB Meta Temp Score: 7.1

VulDB Base Score: 7.0
VulDB Temp Score: 6.7
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 7.4
CNA Vector (MITRE): 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Use after free
CWE: CWE-416 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: No

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Patch
Status: 🔍

0-Day Time: 🔒

Patch: 1957873d2063db11dab780eca75b5e629d1e838d

Timelineinfo

06/25/2026 Advisory disclosed
06/25/2026 +0 days CVE reserved
06/25/2026 +0 days VulDB entry created
06/25/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: 1957873d2063db11dab780eca75b5e629d1e838d
Status: Confirmed

CVE: CVE-2026-57589 (🔒)
GCVE (CVE): GCVE-0-2026-57589
GCVE (VulDB): GCVE-100-373593
CERT Bund: WID-SEC-2026-2066 - OpenBSD: Schwachstelle ermöglicht Privilegieneskalation

Entryinfo

Created: 06/25/2026 06:09
Updated: 06/25/2026 11:59
Changes: 06/25/2026 06:09 (67), 06/25/2026 11:59 (7)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Discussion

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