In the Linux kernel, the following vulnerability has been resolved: mmc: core: Avoid bitfield...

CVE-2026-43484 → View on GitHub ↗ View on CVE.org ↗ View on NVD ↗

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.

Basic information

Type
unreviewed
Severity
medium
Advisory on GitHub
Open advisory ↗
Repository advisory
—
Source code
Not specified
Published (advisory)
2026-05-13 18:30:57 UTC
Updated
2026-06-26 21:32:04 UTC
NVD published
2026-05-13

EPSS Score

Score Percentile
0.11% 1.78%

CVSS Scores

Base score Version Severity Vector
5.5 3.1 —
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.

Identifiers

Type Value
GHSA GHSA-42p4-9577-4wfh ↗
CVE CVE-2026-43484 ↗

References

cvelogic Threat Intelligence