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CVE-2021-26931

MEDIUMCVSS 5.5/10EPSS 0.54%

Last modified

CVE-2021-26931 is a medium-severity vulnerability rated 5.5/10 on the CVSS scale. An issue was discovered in the Linux kernel 2.6.39 through 5.10.16, as used in Xen. Block, net, and SCSI backends consider certain errors a plain bug, deliberately causing a kernel crash. EPSS estimates a 0.54% chance of exploitation in the next 30 days.

Description

An issue was discovered in the Linux kernel 2.6.39 through 5.10.16, as used in Xen. Block, net, and SCSI backends consider certain errors a plain bug, deliberately causing a kernel crash. For errors potentially being at least under the influence of guests (such as out of memory conditions), it isn't correct to assume a plain bug. Memory allocations potentially causing such crashes occur only when Linux is running in PV mode, though. This affects drivers/block/xen-blkback/blkback.c and drivers/xen/xen-scsiback.c.

Metrics

CVSS 3.1
5.5/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS Probability
0.54%

41.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
LinuxLinux Kernel>= 2.6.39, <= 5.10.16
FedoraprojectFedora32
FedoraprojectFedora33
DebianDebian Linux9.0

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2021-26931?
An issue was discovered in the Linux kernel 2.6.39 through 5.10.16, as used in Xen. Block, net, and SCSI backends consider certain errors a plain bug, deliberately causing a kernel crash. For errors potentially being at least under the influence of guests (such as out of memory conditions), it isn't correct to assume a plain bug. Memory allocations potentially causing such crashes occur only when Linux is running in PV mode, though. This affects drivers/block/xen-blkback/blkback.c and drivers/xen/xen-scsiback.c.
How severe is CVE-2021-26931?
CVE-2021-26931 has a CVSS score of 5.5/10 (MEDIUM severity). The EPSS model estimates a 0.54% probability of exploitation in the next 30 days.
How do I fix CVE-2021-26931?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-26931?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST