CVE-2021-47337
5.5 · MEDIUMOverview
CVE-2021-47337 is a medium-severity vulnerability affecting linux linux_kernel. It was published on May 21, 2024 and has a CVSS 3.1 base score of 5.5 (MEDIUM).
This vulnerability has a CVSS 3.1 base score of 5.5, rated MEDIUM. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.
Technical Description
In the Linux kernel, the following vulnerability has been resolved:
scsi: core: Fix bad pointer dereference when ehandler kthread is invalid
Commit 66a834d09293 ("scsi: core: Fix error handling of scsi_host_alloc()")
changed the allocation logic to call put_device() to perform host cleanup
with the assumption that IDA removal and stopping the kthread would
properly be performed in scsi_host_dev_release(). However, in the unlikely
case that the error handler thread fails to spawn, shost->ehandler is set
to ERR_PTR(-ENOMEM).
The error handler cleanup code in scsi_host_dev_release() will call
kthread_stop() if shost->ehandler != NULL which will always be the case
whether the kthread was successfully spawned or not. In the case that it
failed to spawn this has the nasty side effect of trying to dereference an
invalid pointer when kthread_stop() is called. The following splat provides
an example of this behavior in the wild:
scsi host11: error handler thread failed to spawn, error = -4
Remediation
Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| linux | linux_kernel | >= 4.9.273, < 4.9.276 | Affected |
References
Frequently Asked Questions
What is CVE-2021-47337?
CVE-2021-47337 is a medium-severity vulnerability affecting linux linux_kernel. It was published on May 21, 2024 and has a CVSS 3.1 base score of 5.5 (MEDIUM).
How severe is CVE-2021-47337?
This vulnerability has a CVSS 3.1 base score of 5.5, rated MEDIUM. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.
How do I fix or remediate CVE-2021-47337?
Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2021-47337?
CyberStrike's AI-powered security agents can automatically detect CVE-2021-47337 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
AI agents map your attack surface to find vulnerabilities like this one.
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