What is CVE-2026-8863?
Multiple Microsoft-sigend UEFI SHIM bootloaders are vulnerable to SecureBoot bypass. An attacker with administrative privileges or the ability to modify the boot process could use one of the vulnerable shim bootloaders to bypass Secure Boot protections and execute arbitrary code before the operating system loads. Specific UEFI DBX update is required to block these vulnerable boot loaders.
Its CVSS v3 base vector states that the flaw requires local access to the host, needs low-privilege credentials, needs no user interaction, and has high impact on confidentiality, integrity, availability. 12 affected-product entries are recorded, across 7 vendors, listed below. The identifier was first published 141 days ago.
Severity and exploitation probability
- CVSS v3.1 base score
- 7.8 — HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - EPSS (FIRST)
- 0.1% probability of exploitation in the next 30 days, higher than 1.0% of all scored CVEs
- CISA KEV
- Not listed in the CISA Known Exploited Vulnerabilities catalog
- Threadlinqs priority
- 5.9/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- Published
- 2026-06-09, last modified 2026-06-10
Is CVE-2026-8863 being exploited?
Weaponised exploit code for CVE-2026-8863 is publicly available. 1 public proof-of-concept repository is tracked for this identifier. It currently carries a trending score of 18 in the Threadlinqs vulnerability feed.
- 0xbekoo/CVE-2026-8863 (github)
Affected products and versions
- Oracle Corporation: OracleLinux(7.2) shim
- PC-Doctor: Service Center Enterprise, Service Center Drive Erase, Service Center Japan, Service Center, Network Factory for Linux (Bootable Diagnostics), Factory for Linux (Bootable Diagnostics)
- Spyrus: WTGCreator
- Blancco UK: WhiteCanyon WipeDrive
- baramundi software: baramundi Management Suite
- SUSE Linux: OpenSUSE shim
- Finland Matriculation Board: Abitti 1
How to fix CVE-2026-8863
No vendor patch reference has been recorded for CVE-2026-8863 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.
Threat activity tracking CVE-2026-8863
2 tracked threats in the Threadlinqs corpus reference CVE-2026-8863, either in the campaign’s CVE list or as an indicator on the campaign record.
Sources
Enriched from CVE.org, FIRST EPSS, GitHub Security Advisories, public proof-of-concept repositories. Last verified by Threadlinqs on .