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TI-2021-02451 Aliases CVE-2021-3492GHSA-hr5j-7qj8-mpp3

Ubuntu linux kernel shiftfs file system double free vulnerability

Priority MEDIUM 41CWE-401Published · Updated

Key facts

Attack vector
Local
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
Denial of service, Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-401, CWE-415 and the CVSS impact.

Summary

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.

Why it matters now

EPSS 0.01535 74th percentileScored 2026-11-07
Fix Fixed Linux kernel (Ubuntu): 5.8.0-50.56, 5.4.0-72.80

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
UbuntuLinux kernel5.8 kernel to before 5.8.0-50.56; 5.4 kernel to before 5.4.0-72.805.8.0-50.56, 5.4.0-72.80Patch availableCNA
  • Linux kernel VendorUbuntu Affected 5.8 kernel to before 5.8.0-50.56; 5.4 kernel to before 5.4.0-72.80 Fixed in 5.8.0-50.56, 5.4.0-72.80 Patch available CNA

CPE configurations NVD · 2

CPEVersionsRoleVendor
cpe:2.3:o:canonical:ubuntu_linux:*:*:*:*:lts:*:*:*before 18.04; 18.04.1 to before 20.04VulnerableCanonical
cpe:2.3:o:canonical:ubuntu_linux:*:*:*:*:-:*:*:*before 20.10VulnerableCanonical
  • cpe:2.3:o:canonical:ubuntu_linux:*:*:*:*:lts:*:*:* Versions before 18.04; 18.04.1 to before 20.04 Vulnerable ·Canonical
  • cpe:2.3:o:canonical:ubuntu_linux:*:*:*:*:-:*:*:* Versions before 20.10 Vulnerable ·Canonical

Remediation

  • Fix · CNA Linux kernel (Ubuntu) Fixed in 5.8.0-50.56, 5.4.0-72.80

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

Not affected: 4 products
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 7
  • Red Hat Enterprise Linux 8
  • Red Hat Enterprise Linux 9

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-3492
  2. 2026-10-03 Alias added: GHSA-hr5j-7qj8-mpp3

References

Patch 2

Advisory 4

  • TI-2021-02452 Incorrect authorization in Ubuntu linux kernel KEVCVSS 3.1HIGH 8.8
  • TI-2007-05153 Stack-based buffer overflow in the cons_options function in options.c in dhcpd in OpenBSD… CVSS 2.0HIGH 7.2
  • TI-2004-01032 Multiple vulnerabilities in the IGMP functionality for Linux kernel 2.4.22 to 2.4.28, and… CVSS 2.0HIGH 10.0
  • TI-2004-00896 Multiple buffer overflows in libXML 2.6.12 and 2.6.13 (libxml2), and possibly other… CVSS 2.0HIGH 10.0
  • TI-2004-00800 Buffer overflow in the QFILEPATHINFO request handler in Samba 3.0.x through 3.0.7 may… CVSS 2.0HIGH 10.0
  • TI-2004-00962 Buffer overflow in the exif_read_data function in PHP before 4.3.10 and PHP 5.x up to… CVSS 2.0HIGH 10.0
See all 129 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences