CVE-2025-71135: md/raid5: fix possible null-pointer dereferences in raid5_store_group_thread_cnt()

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-01-14 · updated 2026-06-17
Weakness: CWE-476

Description

In the Linux kernel, the following vulnerability has been resolved: md/raid5: fix possible null-pointer dereferences in raid5_store_group_thread_cnt() The variable mddev->private is first assigned to conf and then checked: conf = mddev->private; if (!conf) ... If conf is NULL, then mddev->private is also NULL. In this case, null-pointer dereferences can occur when calling raid5_quiesce(): raid5_quiesce(mddev, true); raid5_quiesce(mddev, false); since mddev->private is assigned to conf again in raid5_quiesce(), and conf is dereferenced in several places, for example: conf->quiesce = 0; wake_up(&conf->wait_for_quiescent); To fix this issue, the function should unlock mddev and return before invoking raid5_quiesce() when conf is NULL, following the existing pattern in raid5_change_consistency_policy().

Affected products

Linux kernel: from 6.12.4 before 6.12.64; from 6.13.1 before 6.18.4; 6.13, 6.19-rc1, 6.19-rc2, 6.19-rc3, 6.19-rc4, 6.19-rc5 (+3) — fixed in 6.12.64, 6.18.4

How to fix

Upgrade to a fixed version: Linux kernel 6.12.64, 6.18.4. Check the vendor advisory for mitigations.

References

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