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VulnerabilityPublished

CVE-2026-8863: Improper Verification of Cryptographic Signature in Oracle Corporation OracleLinux(7.2) shim

Affects Oracle OracleLinux(7.2) shimSource GCVE Database

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Not known to be exploited · CVSS 7.8 High.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 1% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 9 Jun 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: evidence found.

    Public exploit code: GitHub proofs of concept

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), GitHub proofs of concept, the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.

What to do

Affected software

ProductAffectedFixed in
Oracle Corporation OracleLinux(7.2) shimAffected
  • =0.9
Fixed in–

AI-suggested

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.

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.

References

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