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CVE-2021-47577

MEDIUMCVSS 4.7/10EPSS 0.14%

Last modified

CVE-2021-47577 is a medium-severity vulnerability rated 4.7/10 on the CVSS scale. In the Linux kernel, the following vulnerability has been resolved: io-wq: check for wq exit after adding new worker task_work We check IO_WQ_BIT_EXIT before attempting to create a new worker, and wq exit cancels pending work if we have any. But it's possible to have a race between the two, where creation checks exit finding it not set, but we're in the process of exiting. EPSS estimates a 0.14% chance of exploitation in the next 30 days.

Description

In the Linux kernel, the following vulnerability has been resolved: io-wq: check for wq exit after adding new worker task_work We check IO_WQ_BIT_EXIT before attempting to create a new worker, and wq exit cancels pending work if we have any. But it's possible to have a race between the two, where creation checks exit finding it not set, but we're in the process of exiting. The exit side will cancel pending creation task_work, but there's a gap where we add task_work after we've canceled existing creations at exit time. Fix this by checking the EXIT bit post adding the creation task_work. If it's set, run the same cancelation that exit does.

Metrics

CVSS 3.1
4.7/10

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

EPSS Probability
0.14%

3.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersionsUpdate
LinuxLinux Kernel< 5.15.11—
LinuxLinux Kernel5.16Rc1

References

Timeline

Published
Last Modified
Status
Analyzed

Frequently Asked Questions

What is CVE-2021-47577?
In the Linux kernel, the following vulnerability has been resolved: io-wq: check for wq exit after adding new worker task_work We check IO_WQ_BIT_EXIT before attempting to create a new worker, and wq exit cancels pending work if we have any. But it's possible to have a race between the two, where creation checks exit finding it not set, but we're in the process of exiting. The exit side will cancel pending creation task_work, but there's a gap where we add task_work after we've canceled existing creations at exit time. Fix this by checking the EXIT bit post adding the creation task_work. If it's set, run the same cancelation that exit does.
How severe is CVE-2021-47577?
CVE-2021-47577 has a CVSS score of 4.7/10 (MEDIUM severity). The EPSS model estimates a 0.14% probability of exploitation in the next 30 days.
How do I fix CVE-2021-47577?
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-2021-47577?

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

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Source: NVD / NIST