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CVE-2021-47294

MEDIUMCVSS 5.5/10EPSS 0.28%

Last modified

CVE-2021-47294 is a medium-severity vulnerability rated 5.5/10 on the CVSS scale. In the Linux kernel, the following vulnerability has been resolved: netrom: Decrease sock refcount when sock timers expire Commit 63346650c1a9 ("netrom: switch to sock timer API") switched to use sock timer API. It replaces mod_timer() by sk_reset_timer(), and del_timer() by sk_stop_timer(). Function sk_reset_timer() will increase the refcount of sock if it is called on an inactive timer, hence, in case the timer expires, we need to decrease the refcount ourselves in the handler, otherwise, the sock refcount will be unbalanced and the sock will never be freed.. EPSS estimates a 0.28% chance of exploitation in the next 30 days.

Description

In the Linux kernel, the following vulnerability has been resolved: netrom: Decrease sock refcount when sock timers expire Commit 63346650c1a9 ("netrom: switch to sock timer API") switched to use sock timer API. It replaces mod_timer() by sk_reset_timer(), and del_timer() by sk_stop_timer(). Function sk_reset_timer() will increase the refcount of sock if it is called on an inactive timer, hence, in case the timer expires, we need to decrease the refcount ourselves in the handler, otherwise, the sock refcount will be unbalanced and the sock will never be freed.

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
0.28%

19.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersionsUpdate
LinuxLinux Kernel>= 4.4.173, < 4.4.277—
LinuxLinux Kernel>= 4.9.155, < 4.9.277—
LinuxLinux Kernel>= 4.14.98, < 4.14.241—
LinuxLinux Kernel>= 4.19.20, < 4.19.199—
LinuxLinux Kernel>= 5.0, < 5.4.136—
LinuxLinux Kernel>= 5.5, < 5.10.54—
LinuxLinux Kernel>= 5.11, < 5.13.6—
LinuxLinux Kernel3.18.134—
LinuxLinux Kernel4.20.7—
LinuxLinux Kernel5.14Rc1

References

Timeline

Published
Last Modified
Status
Analyzed

Frequently Asked Questions

What is CVE-2021-47294?
In the Linux kernel, the following vulnerability has been resolved: netrom: Decrease sock refcount when sock timers expire Commit 63346650c1a9 ("netrom: switch to sock timer API") switched to use sock timer API. It replaces mod_timer() by sk_reset_timer(), and del_timer() by sk_stop_timer(). Function sk_reset_timer() will increase the refcount of sock if it is called on an inactive timer, hence, in case the timer expires, we need to decrease the refcount ourselves in the handler, otherwise, the sock refcount will be unbalanced and the sock will never be freed.
How severe is CVE-2021-47294?
CVE-2021-47294 has a CVSS score of 5.5/10 (MEDIUM severity). The EPSS model estimates a 0.28% probability of exploitation in the next 30 days.
How do I fix CVE-2021-47294?
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-2021-47294?

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Source: NVD / NIST