CVE-2021-47066

CVE-2021-47066 is a medium-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 5.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Description

In the Linux kernel, the following vulnerability has been resolved: async_xor: increase src_offs when dropping destination page Now we support sharing one page if PAGE_SIZE is not equal stripe size. To support this, it needs to support calculating xor value with different offsets for each r5dev. One offset array is used to record those offsets. In RMW mode, parity page is used as a source page. It sets ASYNC_TX_XOR_DROP_DST before calculating xor value in ops_run_prexor5. So it needs to add src_list and src_offs at the same time. Now it only needs src_list. So the xor value which is calculated is wrong. It can cause data corruption problem. I can reproduce this problem 100% on a POWER8 machine. The steps are: mdadm -CR /dev/md0 -l5 -n3 /dev/sdb1 /dev/sdc1 /dev/sdd1 --size=3G mkfs.xfs /dev/md0 mount /dev/md0 /mnt/test mount: /mnt/test: mount(2) system call failed: Structure needs cleaning.

Frequently asked questions

What is CVE-2021-47066?
In the Linux kernel, the following vulnerability has been resolved: async_xor: increase src_offs when dropping destination page Now we support sharing one page if PAGE_SIZE is not equal stripe size. To support this, it needs to support calculating xor value with different offsets for each r5dev. One offset array is used to record those offsets. In RMW mode, parity page is used as a source page. It sets ASYNC_TX_XOR_DROP_DST before calculating xor value in ops_run_prexor5. So it needs to add src_list and src_offs at the same time. Now it only needs src_list. So the xor value which is calculated is wrong. It can cause data corruption problem. I can reproduce this problem 100% on a POWER8 machine. The steps are: mdadm -CR /dev/md0 -l5 -n3 /dev/sdb1 /dev/sdc1 /dev/sdd1 --size=3G mkfs.xfs /dev/md0 mount /dev/md0 /mnt/test mount: /mnt/test: mount(2) system call failed: Structure needs cleaning.
How severe is CVE-2021-47066?
CVE-2021-47066 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-47066 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (14th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-47066?
CVE-2021-47066 affects Linux Linux Kernel. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-47066?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2021-47066 have an EU (EUVD) identifier?
Yes. CVE-2021-47066 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-33714.
When was CVE-2021-47066 published?
CVE-2021-47066 was published on 2024-02-29 and last updated on 2026-06-17.

References

Affected products (1)

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