CVE-2026-43484 PUBLISHED

mmc: core: Avoid bitfield RMW for claim/retune flags

Assigner: Linux
Reserved: 01.05.2026 Published: 13.05.2026 Updated: 13.05.2026

In the Linux kernel, the following vulnerability has been resolved:

mmc: core: Avoid bitfield RMW for claim/retune flags

Move claimed and retune control flags out of the bitfield word to avoid unrelated RMW side effects in asynchronous contexts.

The host->claimed bit shared a word with retune flags. Writes to claimed in __mmc_claim_host() or retune_now in mmc_mq_queue_rq() can overwrite other bits when concurrent updates happen in other contexts, triggering spurious WARN_ON(!host->claimed). Convert claimed, can_retune, retune_now and retune_paused to bool to remove shared-word coupling.

Product Status

Vendor Linux
Product Linux
Versions Default: unaffected
  • affected from 6c0cedd1ef9527ef13e66875746570e76a3188a7 to 41dce4dae583a8ce06a7ebf4ce704c46a142957c (excl.)
  • affected from 6c0cedd1ef9527ef13e66875746570e76a3188a7 to bb7fc2498c3bb25fa6a91f22f4760005325cfbd5 (excl.)
  • affected from 6c0cedd1ef9527ef13e66875746570e76a3188a7 to 270277c2ab631044867adb1bd2f2433d3892de6e (excl.)
  • affected from 6c0cedd1ef9527ef13e66875746570e76a3188a7 to 45038e03f15e992c48603fff8c6b1c9be5397ac9 (excl.)
  • affected from 6c0cedd1ef9527ef13e66875746570e76a3188a7 to 0e06cc511c61cff1591e5435a207759adcc76b6d (excl.)
  • affected from 6c0cedd1ef9527ef13e66875746570e76a3188a7 to d3a3caf44c8ec26f5d63dc17c1c7242effa60ebc (excl.)
  • affected from 6c0cedd1ef9527ef13e66875746570e76a3188a7 to 901084c51a0a8fb42a3f37d2e9c62083c495f824 (excl.)
Vendor Linux
Product Linux
Versions Default: affected
  • Version 4.15 is affected
  • unaffected from 0 to 4.15 (excl.)
  • unaffected from 5.15.203 to 5.15.* (incl.)
  • unaffected from 6.1.167 to 6.1.* (incl.)
  • unaffected from 6.6.130 to 6.6.* (incl.)
  • unaffected from 6.12.78 to 6.12.* (incl.)
  • unaffected from 6.18.19 to 6.18.* (incl.)
  • unaffected from 6.19.9 to 6.19.* (incl.)
  • unaffected from 7.0 to * (incl.)

References