Critical Out-of-Bounds Write Vulnerability in Intel Microcode Packages
Summary
CVE-2025-26403: Out-of-bounds write in the memory subsystem for some Intel(R) Xeon(R) 6 processors when using Intel(R) SGX or Intel(R) TDX may allow a privileged user to potentially enable escalation of privilege via local access. Affects intel-ucode versions < 20250812-r0. Fixed in 20250812-r0. How to fix ↓
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Background
Intel Microcode is a crucial component in the functioning of Intel processors, including the Xeon series. It provides updates to the processor's firmware, enhancing performance and security. This vulnerability affects multiple Debian versions (11, 12, 13, and 14) of the intel-microcode package, which is essential for ensuring the proper operation of Intel processors. The vulnerability can potentially allow unauthorized escalation of privileges, posing a significant risk to systems relying on these packages.
Vulnerability Detail
The vulnerability, identified as CVE-2025-26403, is an out-of-bounds write issue in the memory subsystem specifically affecting some Intel(R) Xeon(R) 6 processors when utilizing Intel(R) SGX or Intel(R) TDX. This flaw allows a privileged user to potentially escalate privileges through local access, which could lead to unauthorized access to sensitive information or control over the system. The vulnerability originates from improper handling of memory operations, which can be exploited under certain conditions.
How To Fix
Minimum fixed version
20250812-r0
This is the first release that contains the fix.
sudo apk add --upgrade intel-ucodeTip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a temporary workaround, consider limiting access to the affected systems and monitoring for any unusual activity. Additionally, disabling Intel SGX or TDX features may mitigate the risk until a patch is applied.
Conclusion
The CVE-2025-26403 vulnerability poses a significant risk to systems using Intel Microcode packages across multiple Debian versions. It is crucial to apply the necessary updates to mitigate the risk of privilege escalation. Users are encouraged to monitor their systems and utilize tools like Vulert for real-time vulnerability alerts.
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FAQ
CVE-2025-26403 is a critical vulnerability affecting Intel Microcode packages that allows for potential privilege escalation due to an out-of-bounds write in the memory subsystem.
The vulnerability affects Intel Microcode packages in Debian versions 11, 12, 13, and 14, specifically for Intel Xeon processors.
You can use Vulert's playground at Vulert Scanner to check if your application is affected by this vulnerability without any signup.
If an immediate update is not possible, consider implementing access restrictions and monitoring for unusual activities as a temporary workaround.
Detailed information about CVE-2025-26403 can be found in the official CVE database and through security advisories from Debian.
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