CVE-2026-43484

Description

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.

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EPSS — Exploit Prediction

0.0003

Probability of exploitation

0.10%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

References

Other References

https://git.kernel.org/stable/c/0e06cc511c61cff1591e5435a207759adcc76b6d https://git.kernel.org/stable/c/270277c2ab631044867adb1bd2f2433d3892de6e https://git.kernel.org/stable/c/41dce4dae583a8ce06a7ebf4ce704c46a142957c https://git.kernel.org/stable/c/45038e03f15e992c48603fff8c6b1c9be5397ac9 https://git.kernel.org/stable/c/901084c51a0a8fb42a3f37d2e9c62083c495f824 https://git.kernel.org/stable/c/bb7fc2498c3bb25fa6a91f22f4760005325cfbd5 https://git.kernel.org/stable/c/d3a3caf44c8ec26f5d63dc17c1c7242effa60ebc

Frequently Asked Questions

What is CVE-2026-43484? +

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.

How do I check if I'm vulnerable to CVE-2026-43484? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.