Bug 2535109 (CVE-2026-89918) - CVE-2026-89918 kernel: KVM: arm64: Correctly handle end of VA space TLBI invalidation
Summary: CVE-2026-89918 kernel: KVM: arm64: Correctly handle end of VA space TLBI inva...
Keywords:
Status: NEW
Alias: CVE-2026-89918
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-09-16 10:47 UTC by OSIDB Bzimport
Modified: 2026-11-04 15:04 UTC (History)
17 users (show)

Fixed In Version:
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Description OSIDB Bzimport 2026-09-16 10:47:15 UTC
In the Linux kernel, the following vulnerability has been resolved:

KVM: arm64: Correctly handle end of VA space TLBI invalidation

Our TLB invalidation by VA code is based on comparing two ranges,
one defined by the TLB, and one defined by the TLBI instruction.

Each range is defined by a start and a size. However, the way the
comparison is done doesn't account for address rollover, as it
compares an address with (base + size). This works nicely until
this expression represent the last page/block in the TTBR1 VA space,
as the result is a big fat 0. And a failed TLB invalidation.

Rewrite the comparison in a way that is immune to the address
rollover (making the end address inclusive instead of exclusive),
and move this into a common helper that is used by both VA and IPA
invalidations, as suggested by Hyunwoo Kim (although the IPA version
didn't suffer from this particular problem, obviously).


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