CVE-2025-27465mediumCWE-755

CVE-2025-27465: medium-severity vulnerability in Xen

x86: Incorrect stubs exception handling for flags recovery

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13Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 4.3epss 0.7%
In short

Xen hypervisor incorrectly handles exceptions when replaying certain x86 instructions that need to recover arithmetic flags, treating recoverable errors as fatal crashes instead of handling them gracefully.

Technical detail

CWE-755 vulnerability in Xen's stub-based instruction emulation where exception metadata is misconfigured for replayed instructions with flags recovery logic, causing unhandled exceptions to terminate the system instead of being caught and processed by exception handlers. Affects x86 platforms running Xen when specific instruction patterns trigger both exception conditions and flags recovery requirements.

Summary generated and translated by AI from the official description.
Certain instructions need intercepting and emulating by Xen. In some cases Xen emulates the instruction by replaying it, using an executable stub. Some instructions may raise an exception, which is supposed to be handled gracefully. Certain replayed instructions have additional logic to set up and recover the changes to the arithmetic flags. For replayed instructions where the flags recovery logic is used, the metadata for exception handling was incorrect, preventing Xen from handling the the exception gracefully, treating it as fatal instead.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
Affected products
Xen · Xen
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