CVE-2021-47294

MEDIUM
Published May 21, 2024 Modified Jun 23, 2025 CWE-672

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.

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CVSS v3.1 Score

5.5
MEDIUM
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Weakness Type (CWE)

CWE-672 CWE-672

Affected Products

Vendor Product
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel

References

Advisories & Patches

https://git.kernel.org/stable/c/25df44e90ff5959b5c24ad361b648504a7e39ef3 https://git.kernel.org/stable/c/48866fd5c361ea417ed24b43fc2a7dc2f5b060ef https://git.kernel.org/stable/c/517a16b1a88bdb6b530f48d5d153478b2552d9a8 https://git.kernel.org/stable/c/6811744bd0efb9e472cb15d066cdb460beb8cb8a https://git.kernel.org/stable/c/853262355518cd1247515b74e83fabf038aa6c29 https://git.kernel.org/stable/c/9619cc7d97c3aa8ed3cfd2b8678b74fb6d6c7950 https://git.kernel.org/stable/c/a01634bf91f2b6c42583770eb6815fb6d1e251cf https://git.kernel.org/stable/c/bc1660206c3723c37ed4d622ad81781f1e987250 https://git.kernel.org/stable/c/25df44e90ff5959b5c24ad361b648504a7e39ef3 https://git.kernel.org/stable/c/48866fd5c361ea417ed24b43fc2a7dc2f5b060ef https://git.kernel.org/stable/c/517a16b1a88bdb6b530f48d5d153478b2552d9a8 https://git.kernel.org/stable/c/6811744bd0efb9e472cb15d066cdb460beb8cb8a https://git.kernel.org/stable/c/853262355518cd1247515b74e83fabf038aa6c29 https://git.kernel.org/stable/c/9619cc7d97c3aa8ed3cfd2b8678b74fb6d6c7950 https://git.kernel.org/stable/c/a01634bf91f2b6c42583770eb6815fb6d1e251cf https://git.kernel.org/stable/c/bc1660206c3723c37ed4d622ad81781f1e987250

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. It has a CVSS v3.1 base score of 5.5 (MEDIUM).
How severe is CVE-2021-47294? +
CVE-2021-47294 has a CVSS v3.1 score of 5.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.
What products are affected by CVE-2021-47294? +
CVE-2021-47294 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.
How do I check if I'm vulnerable to CVE-2021-47294? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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