Bug 2365287 (CVE-2025-37846)

Summary: CVE-2025-37846 kernel: arm64: mops: Do not dereference src reg for a set operation
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: dfreiber, drow, jburrell, vkumar
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Hardware: All   
OS: Linux   
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Description OSIDB Bzimport 2025-05-09 07:03:25 UTC 
In the Linux kernel, the following vulnerability has been resolved:

arm64: mops: Do not dereference src reg for a set operation

The source register is not used for SET* and reading it can result in
a UBSAN out-of-bounds array access error, specifically when the MOPS
exception is taken from a SET* sequence with XZR (reg 31) as the
source. Architecturally this is the only case where a src/dst/size
field in the ESR can be reported as 31.

Prior to 2de451a329cf662b the code in do_el0_mops() was benign as the
use of pt_regs_read_reg() prevented the out-of-bounds access.
Comment 1 Michal Findra 2025-05-09 07:44:10 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025050917-CVE-2025-37846-9afa@gregkh/T