CWE-347: Improper Verification of Cryptographic Signature in Oracle Corporation OracleLinux(7.2) shim (CVE-2026-8863)
CVE-2026-8863 is a vulnerability in OracleLinux(7.2) shim version 0.9 involving improper verification of cryptographic signatures. This flaw allows an attacker with administrative privileges or the ability to modify the boot process to bypass Secure Boot protections by exploiting Microsoft-signed UEFI SHIM bootloaders. Successful exploitation could enable arbitrary code execution before the operating system loads. No official patch or remediation guidance is currently provided, but a specific UEFI DBX update is required to block the vulnerable boot loaders.
AI Analysis
Technical Summary
This vulnerability (CVE-2026-8863) affects OracleLinux(7.2) shim version 0.9 and is classified under CWE-347 (Improper Verification of Cryptographic Signature) and CWE-354. The issue arises from multiple Microsoft-signed UEFI SHIM bootloaders that fail to properly verify cryptographic signatures, allowing Secure Boot bypass. An attacker with local administrative privileges or control over the boot process can exploit this to execute arbitrary code early in the boot sequence, potentially compromising system integrity. The vulnerability has a CVSS 3.1 base score of 7.8, indicating high severity. No vendor advisory or patch links are currently available, and remediation involves applying a specific UEFI DBX update to block the vulnerable bootloaders.
Potential Impact
An attacker with administrative privileges or the ability to modify the boot process can bypass Secure Boot protections, enabling execution of arbitrary code before the operating system loads. This compromises system integrity, confidentiality, and availability as indicated by the CVSS vector (C:H/I:H/A:H).
Mitigation Recommendations
No official patch or remediation level is currently provided by the vendor. Remediation involves applying a specific UEFI DBX update to block the vulnerable Microsoft-signed shim bootloaders. Organizations should monitor vendor advisories for updates and apply the UEFI DBX update as soon as it becomes available.
CWE-347: Improper Verification of Cryptographic Signature in Oracle Corporation OracleLinux(7.2) shim (CVE-2026-8863)
Description
CVE-2026-8863 is a vulnerability in OracleLinux(7.2) shim version 0.9 involving improper verification of cryptographic signatures. This flaw allows an attacker with administrative privileges or the ability to modify the boot process to bypass Secure Boot protections by exploiting Microsoft-signed UEFI SHIM bootloaders. Successful exploitation could enable arbitrary code execution before the operating system loads. No official patch or remediation guidance is currently provided, but a specific UEFI DBX update is required to block the vulnerable boot loaders.
CVSS v3.1
Score 7.8high
Affected software
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability (CVE-2026-8863) affects OracleLinux(7.2) shim version 0.9 and is classified under CWE-347 (Improper Verification of Cryptographic Signature) and CWE-354. The issue arises from multiple Microsoft-signed UEFI SHIM bootloaders that fail to properly verify cryptographic signatures, allowing Secure Boot bypass. An attacker with local administrative privileges or control over the boot process can exploit this to execute arbitrary code early in the boot sequence, potentially compromising system integrity. The vulnerability has a CVSS 3.1 base score of 7.8, indicating high severity. No vendor advisory or patch links are currently available, and remediation involves applying a specific UEFI DBX update to block the vulnerable bootloaders.
Potential Impact
An attacker with administrative privileges or the ability to modify the boot process can bypass Secure Boot protections, enabling execution of arbitrary code before the operating system loads. This compromises system integrity, confidentiality, and availability as indicated by the CVSS vector (C:H/I:H/A:H).
Mitigation Recommendations
No official patch or remediation level is currently provided by the vendor. Remediation involves applying a specific UEFI DBX update to block the vulnerable Microsoft-signed shim bootloaders. Organizations should monitor vendor advisories for updates and apply the UEFI DBX update as soon as it becomes available.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- certcc
- Date Reserved
- 2026-05-18T19:41:10.790Z
- Cvss Version
- null
- State
- PUBLISHED
- Remediation Level
- null
- Gcve Source
- db.gcve.eu
Threat ID: 6a2866f48dd33fbd85722264
Added to database: 06/09/2026, 19:18:12 UTC
Last enriched: 06/17/2026, 15:11:23 UTC
Last updated: 07/31/2026, 19:23:00 UTC
Views: 91
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