CVE-2021-47294
netrom: Decrease sock refcount when sock timers expire
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.
INFO
Published Date :
May 21, 2024, 3:15 p.m.
Last Modified :
June 23, 2025, 8:19 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Update the Linux kernel to a patched version.
- Reboot the system after the kernel update.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2021-47294.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2021-47294 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2021-47294
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2021-47294 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2021-47294 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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Initial Analysis by [email protected]
Jun. 23, 2025
Action Type Old Value New Value Added CVSS V3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Added CWE CWE-672 Added CPE Configuration OR *cpe:2.3:o:linux:linux_kernel:5.14:rc1:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:5.14:rc2:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.5 up to (excluding) 5.10.54 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.11 up to (excluding) 5.13.6 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 4.14.98 up to (excluding) 4.14.241 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 4.19.20 up to (excluding) 4.19.199 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 4.4.173 up to (excluding) 4.4.277 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 4.9.155 up to (excluding) 4.9.277 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.0 up to (excluding) 5.4.136 *cpe:2.3:o:linux:linux_kernel:3.18.134:*:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:4.20.7:*:*:*:*:*:*:* Added Reference Type CVE: https://git.kernel.org/stable/c/25df44e90ff5959b5c24ad361b648504a7e39ef3 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/25df44e90ff5959b5c24ad361b648504a7e39ef3 Types: Patch Added Reference Type CVE: https://git.kernel.org/stable/c/48866fd5c361ea417ed24b43fc2a7dc2f5b060ef Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/48866fd5c361ea417ed24b43fc2a7dc2f5b060ef Types: Patch Added Reference Type CVE: https://git.kernel.org/stable/c/517a16b1a88bdb6b530f48d5d153478b2552d9a8 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/517a16b1a88bdb6b530f48d5d153478b2552d9a8 Types: Patch Added Reference Type CVE: https://git.kernel.org/stable/c/6811744bd0efb9e472cb15d066cdb460beb8cb8a Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/6811744bd0efb9e472cb15d066cdb460beb8cb8a Types: Patch Added Reference Type CVE: https://git.kernel.org/stable/c/853262355518cd1247515b74e83fabf038aa6c29 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/853262355518cd1247515b74e83fabf038aa6c29 Types: Patch Added Reference Type CVE: https://git.kernel.org/stable/c/9619cc7d97c3aa8ed3cfd2b8678b74fb6d6c7950 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/9619cc7d97c3aa8ed3cfd2b8678b74fb6d6c7950 Types: Patch Added Reference Type CVE: https://git.kernel.org/stable/c/a01634bf91f2b6c42583770eb6815fb6d1e251cf Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/a01634bf91f2b6c42583770eb6815fb6d1e251cf Types: Patch Added Reference Type CVE: https://git.kernel.org/stable/c/bc1660206c3723c37ed4d622ad81781f1e987250 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/bc1660206c3723c37ed4d622ad81781f1e987250 Types: Patch -
CVE Modified by af854a3a-2127-422b-91ae-364da2661108
Nov. 21, 2024
Action Type Old Value New Value Added Reference https://git.kernel.org/stable/c/25df44e90ff5959b5c24ad361b648504a7e39ef3 Added Reference https://git.kernel.org/stable/c/48866fd5c361ea417ed24b43fc2a7dc2f5b060ef Added Reference https://git.kernel.org/stable/c/517a16b1a88bdb6b530f48d5d153478b2552d9a8 Added Reference https://git.kernel.org/stable/c/6811744bd0efb9e472cb15d066cdb460beb8cb8a Added Reference https://git.kernel.org/stable/c/853262355518cd1247515b74e83fabf038aa6c29 Added Reference https://git.kernel.org/stable/c/9619cc7d97c3aa8ed3cfd2b8678b74fb6d6c7950 Added Reference https://git.kernel.org/stable/c/a01634bf91f2b6c42583770eb6815fb6d1e251cf Added Reference https://git.kernel.org/stable/c/bc1660206c3723c37ed4d622ad81781f1e987250 -
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
May. 28, 2024
Action Type Old Value New Value -
CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
May. 21, 2024
Action Type Old Value New Value Added 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. Added Reference kernel.org https://git.kernel.org/stable/c/853262355518cd1247515b74e83fabf038aa6c29 [No types assigned] Added Reference kernel.org https://git.kernel.org/stable/c/a01634bf91f2b6c42583770eb6815fb6d1e251cf [No types assigned] Added Reference kernel.org https://git.kernel.org/stable/c/48866fd5c361ea417ed24b43fc2a7dc2f5b060ef [No types assigned] Added Reference kernel.org https://git.kernel.org/stable/c/9619cc7d97c3aa8ed3cfd2b8678b74fb6d6c7950 [No types assigned] Added Reference kernel.org https://git.kernel.org/stable/c/25df44e90ff5959b5c24ad361b648504a7e39ef3 [No types assigned] Added Reference kernel.org https://git.kernel.org/stable/c/6811744bd0efb9e472cb15d066cdb460beb8cb8a [No types assigned] Added Reference kernel.org https://git.kernel.org/stable/c/bc1660206c3723c37ed4d622ad81781f1e987250 [No types assigned] Added Reference kernel.org https://git.kernel.org/stable/c/517a16b1a88bdb6b530f48d5d153478b2552d9a8 [No types assigned]