CVE Database · CVE-2026-23553
CVSS v3.1
2.9
EPSS
0.13%
Published
Jan 28, 2026
Modified
Feb 9, 2026
Public PoC / Exploit
All weaponized →No public PoC or exploit code indexed for this CVE.
Links to public security research (Exploit-DB, Nuclei, Trickest, GitHub) for defensive use only.
Description
In the context switch logic Xen attempts to skip an IBPB in the case of a vCPU returning to a CPU on which it was the previous vCPU to run. While safe for Xen's isolation between vCPUs, this prevents the guest kernel correctly isolating between tasks. Consider: 1) vCPU runs on CPU A, running task 1. 2) vCPU moves to CPU B, idle gets scheduled on A. Xen skips IBPB. 3) On CPU B, guest kernel switches from task 1 to 2, issuing IBPB. 4) vCPU moves back to CPU A. Xen skips IBPB again. Now, task 2 is running on CPU A with task 1's training still in the BTB.
CVSS Vector
CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:NWeaknesses (CWE)
Affected Products (1)
References (3)