CVE & CISA-KEV Catalog

CVE-2021-47294

MEDIUM
5.5
CVSS v3
NVD

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.

How to fix

Remediation Available
linuxDebian
Fixed in:5.10.70-1CVE-2021-47294
Fixed in:5.14.6-1CVE-2021-47294
Fixed in:5.14.6-1CVE-2021-47294
Fixed in:5.14.6-1CVE-2021-47294
linuxUbuntu
Fixed in:4.4.0-274.308USN-7863-1
linux-awsUbuntu
Fixed in:4.4.0-1149.155USN-7863-1
Fixed in:4.4.0-1187.202USN-7863-1
linux-fipsUbuntu
Fixed in:4.4.0-1119.126USN-7865-1
linux-image-4.4.0-1119-fipsUbuntu
Fixed in:4.4.0-1119.126USN-7865-1
linux-image-4.4.0-1149-awsUbuntu
Fixed in:4.4.0-1149.155USN-7863-1
linux-image-4.4.0-1150-kvmUbuntu
Fixed in:4.4.0-1150.161USN-7863-1
linux-image-4.4.0-1187-awsUbuntu
Fixed in:4.4.0-1187.202USN-7863-1
linux-image-4.4.0-274-genericUbuntu
Fixed in:4.4.0-274.308~14.04.1USN-7863-1
Fixed in:4.4.0-274.308USN-7863-1
linux-image-4.4.0-274-lowlatencyUbuntu
Fixed in:4.4.0-274.308~14.04.1USN-7863-1
Fixed in:4.4.0-274.308USN-7863-1
linux-image-awsUbuntu
Fixed in:4.4.0.1149.146USN-7863-1
Fixed in:4.4.0.1187.191USN-7863-1
linux-image-fipsUbuntu
Fixed in:4.4.0.1119.120USN-7865-1
linux-image-genericUbuntu
Fixed in:4.4.0.274.280USN-7863-1
linux-image-generic-lts-xenialUbuntu
Fixed in:4.4.0.274.308~14.04.1USN-7863-1
Fixed in:4.4.0.274.280USN-7863-1
linux-image-kvmUbuntu
Fixed in:4.4.0.1150.147USN-7863-1
linux-image-lowlatencyUbuntu
Fixed in:4.4.0.274.280USN-7863-1
linux-image-lowlatency-lts-xenialUbuntu
Fixed in:4.4.0.274.308~14.04.1USN-7863-1
Fixed in:4.4.0.274.280USN-7863-1
linux-image-virtualUbuntu
Fixed in:4.4.0.274.280USN-7863-1
linux-image-virtual-lts-xenialUbuntu
Fixed in:4.4.0.274.308~14.04.1USN-7863-1
Fixed in:4.4.0.274.280USN-7863-1
linux-kvmUbuntu
Fixed in:4.4.0-1150.161USN-7863-1
linux-lts-xenialUbuntu
Fixed in:4.4.0-274.308~14.04.1USN-7863-1

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorLocal
Attack ComplexityLow
Privileges RequiredLow
User InteractionNone
ScopeUnchanged

Impact

ConfidentialityNone
IntegrityNone
AvailabilityHigh

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

Exploit Intelligence

0.28%probability of exploitation in 30 days
20thpercentile

Low risk: more likely to be exploited than 20% of all known CVEs.

References

Related Vulnerabilities

Other CWE-672 vulnerabilities, ordered by exploit likelihood. View all

CVESeverityCVSSEPSSExploitedFix
CVE-2024-23638Medium6.560%-Fix
CVE-2020-11027Medium6.114%-Fix
CVE-2019-17638Critical9.411%-Fix
CVE-2009-3547High7.04.9%--
CVE-2019-15691High7.24.7%-Fix
CVE-2020-24030Critical9.82.7%--
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-06-23.