Bug 2458150 (CVE-2026-3842) - CVE-2026-3842 qemu-kvm: hyperv/syndbg: missing mapped-length guard after cpu_physical_memory_map causes host OOB write
Summary: CVE-2026-3842 qemu-kvm: hyperv/syndbg: missing mapped-length guard after cpu_...
Keywords:
Status: NEW
Alias: CVE-2026-3842
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
high
high
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On: 2458151
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-04-14 07:34 UTC by OSIDB Bzimport
Modified: 2026-04-14 08:12 UTC (History)
0 users

Fixed In Version:
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Description OSIDB Bzimport 2026-04-14 07:34:16 UTC 
If cpu_physical_memory_map() returns a length shorter than the one that was passed into the function, writing the full out_len bytes causes an access beyond the memory allocated to the guest; or in the case of the MMIO bounce buffer, an out-of-bounds access in a heap-allocated object.

Upstream fix:
https://gitlab.com/qemu-project/qemu/-/commit/4f28b87fdd24df2049626106b7c24d0180952115
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