vulntracker.iovulntracker.io
© 2026 vulntracker.io

CVE-2021-3492

Ubuntu linux kernel shiftfs file system double free vulnerability

HIGH
7.8
CVSS Score
Published: April 17, 2021 at 04:20 AM UTC
Updated: June 17, 2026 at 04:05 AM UTC
2 products affected across 2 vendorsUbuntu LinuxLinux kernel

Using Linux kernel by Ubuntu?

Get instant alerts when new vulnerabilities affect Linux kernel - before attackers find them.

Real-time alertsTrack your software stackFree plan available
Start FreeSign In
Severity
HIGH7.8
Exploit prediction
EPSS 2%

Description

Shiftfs, an out-of-tree stacking file system included in Ubuntu Linux kernels, did not properly handle faults occurring during copy_from_user() correctly. These could lead to either a double-free situation or memory not being freed at all. An attacker could use this to cause a denial of service (kernel memory exhaustion) or gain privileges via executing arbitrary code. AKA ZDI-CAN-13562.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Ubuntu Linux· Canonicalrubygems
95%
v < 18.04v < 20.1018.04.1 ≤ v < 20.04
Affected range stops below 18.04, so it looks safe — our inference, not a vendor statement
Affected range stops below 20.04, so it looks safe — our inference, not a vendor statement
Affected range stops below 20.10, so it looks safe — our inference, not a vendor statement
Linux kernel· Ubuntu
60%
5.4 kernel ≤ v < 5.4.0-72.805.8 kernel ≤ v < 5.8.0-50.565.4 kernel5.8 kernel
Affected range stops below 5.4.0-72.80, so it looks safe — our inference, not a vendor statement
Affected range stops below 5.8.0-50.56, so it looks safe — our inference, not a vendor statement

References (6)

x_refsource_MISCThird Party AdvisoryVDB Entry
Source: [email protected]
http://packetstormsecurity.com/files/162614/Kernel-Live-Patch-Security-Notice-LSN-0077-1.html
x_refsource_MISCMailing ListPatchVendor Advisory
Source: [email protected]
https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/focal/commit/?id=25c891a949bf918b59cbc6e4932015ba4c35c333
x_refsource_MISCMailing ListPatchVendor Advisory
Source: [email protected]
https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/focal/commit/?id=8fee52ab9da87d82bc6de9ebb3480fff9b4d53e6
x_refsource_MISCVendor Advisory
Source: [email protected]
https://ubuntu.com/security/notices/USN-4917-1
x_refsource_MISCMailing ListThird Party Advisory
Source: [email protected]
https://www.openwall.com/lists/oss-security/2021/04/16/2
x_refsource_MISCThird Party AdvisoryVDB Entry
Source: [email protected]
https://www.zerodayinitiative.com/advisories/ZDI-21-422/

CVSS

7.8HIGH[email protected]
Attack Vector
LOCAL
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-401CWE-415

Get alerted

Stop reading CVE feeds looking for your own stack

Track the products you run and VulnTracker tells you when a new CVE affects them — with what is known about fixing it, and nothing about the rest.

Create accountSign in
Free plan, no card