Linux Kernel: array_index_nospec misuse causes speculative safety flaw
CVE-2026-23354 Published on March 25, 2026
x86/fred: Correct speculative safety in fred_extint()
In the Linux kernel, the following vulnerability has been resolved:
x86/fred: Correct speculative safety in fred_extint()
array_index_nospec() is no use if the result gets spilled to the stack, as
it makes the believed safe-under-speculation value subject to memory
predictions.
For all practical purposes, this means array_index_nospec() must be used in
the expression that accesses the array.
As the code currently stands, it's the wrong side of irqentry_enter(), and
'index' is put into %ebp across the function call.
Remove the index variable and reposition array_index_nospec(), so it's
calculated immediately before the array access.
Products Associated with CVE-2026-23354
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Affected Versions
Linux:- Version 14619d912b658ecd9573fb88400d3830a29cadcb and below 3bc5887b0a2b06d2d9c22f1f4f8500490b3ae643 is affected.
- Version 14619d912b658ecd9573fb88400d3830a29cadcb and below e58f1a9b0677de24dcfee0b21393446ec92ff120 is affected.
- Version 14619d912b658ecd9573fb88400d3830a29cadcb and below 92caa5274b99cb6729177232a029ce0dfa6c5f7b is affected.
- Version 14619d912b658ecd9573fb88400d3830a29cadcb and below aa280a08e7d8fae58557acc345b36b3dc329d595 is affected.
- Version 6.9 is affected.
- Before 6.9 is unaffected.
- Version 6.12.77, <= 6.12.* is unaffected.
- Version 6.18.17, <= 6.18.* is unaffected.
- Version 6.19.7, <= 6.19.* is unaffected.
- Version 7.0-rc2, <= * is unaffected.