CVE-2021-47294

Medium

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.

Package Linux Kernel
Published 2024-05-21
Last modified 2025-06-23
CVSS version 3.1
Patch available
Yes

CVSS 3.1 score

5.5

out of 10
Medium
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
High
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Weakness type

CWE-672

CVE-2021-47294 is classified as CWE-672

See CWE-672 on MITRE CWE for full details on this weakness type.

Affected versions

Linux kernel versions 4.4.173, 4.9.155, 4.14.98, 4.19.20, 3.18.134, 4.20.7, 5.0 and later are affected. Fixed in 4.4.277, 4.9.277, 4.14.241, 4.19.199, 5.4.136, 5.10.54, 5.13.6, 5.14 and their respective stable series.

Affected from
≥ 4.4.173 ≥ 4.9.155 ≥ 4.14.98 ≥ 4.19.20 ≥ 3.18.134 ≥ 4.20.7 ≥ 5.0
Fixed in
✓ 4.4.277 4.4.x ✓ 4.9.277 4.9.x ✓ 4.14.241 4.14.x ✓ 4.19.199 4.19.x ✓ 5.4.136 5.4.x ✓ 5.10.54 5.10.x ✓ 5.13.6 5.13.x ✓ 5.14

References

8 total
Showing 5 of 8 references View all on NVD

Frequently asked questions

  • What is CVE-2021-47294?

    CVE-2021-47294 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10 . It affects Linux kernel versions from 4.4.173 onward and has been patched in 4.4.277, 4.9.277, 4.14.241 and others. CVE-2021-47294 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

  • What is the CVSS score for CVE-2021-47294?

    CVE-2021-47294 has a CVSS score of 5.5 out of 10, rated Medium severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H .

  • Is there a patch available for CVE-2021-47294?

    Yes. CVE-2021-47294 has been patched. Fixed versions include 4.4.277, 4.9.277, 4.14.241 and others. If you are running Linux kernel 4.4.173 or later up to the fix versions, apply the relevant patch for your kernel branch.

  • Is CVE-2021-47294 actively exploited?

    No. CVE-2021-47294 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

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