7.1

CVE-2021-47066: async_xor: increase src_offs when dropping destination page

Modified
AliasesUBUNTU-CVE-2021-47066DEBIAN-CVE-2021-47066
Published 29-02-2024Last modified 05-08-2026

Vulnerability summary

CVE-2021-47066 is a high (CVSS 7.1) vulnerability in linux. EPSS estimates a 0.24% chance of exploitation in the next 30 days, higher than 14.4% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 7.1, local access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
7.1/10
010
High · v3.1 (CVE.org)
EPSS score
0.24%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Timeline

  1. 29-02-2024
    PublishedVulnerability first disclosed.
  2. 05-08-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.24%

Chance of exploitation in the next 30 days

Percentile

14%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.24% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

No weakness data has been published for this record.

Affected systems

Version check

Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Ubuntu62 products
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
  • linux-aws-5.13All versions (No fix recorded)
  • linux-aws-5.19All versions (No fix recorded)
Linux2 products
  • linux≥ 29bcff787a2593b2126cfaff612c0b4e560022e9, < cab2e8e5997b592fdb7d02cf2387b4b8e3057174 | ≥ 29bcff787a2593b2126cfaff612c0b4e560022e9, < 29ffa50f33de824b5491f8239c88c4a0efdd03af | ≥ 29bcff787a2593b2126cfaff612c0b4e560022e9, < 53f8208e11abd6dde9480dfcb97fecdb1bc2ac18 | ≥ 29bcff787a2593b2126cfaff612c0b4e560022e9, < ceaf2966ab082bbc4d26516f97b3ca8a676e2af8 | 5.10
  • linux_kernel≥ 5.10, < 5.10.37 | ≥ 5.11, < 5.11.21 | ≥ 5.12, < 5.12.4
Debian1 product
  • linux< 5.10.38-1

3 vendors · 65 products

References

8 links