CVE-2021-47119

ext4: fix memory leak in ext4_fill_super

Published Mar 15, 2024 CVSS 3.1 · 5.5 Medium EPSS < 1% KEV · Not listed
Description
In the Linux kernel, the following vulnerability has been resolved:

ext4: fix memory leak in ext4_fill_super

Buffer head references must be released before calling kill_bdev();
otherwise the buffer head (and its page referenced by b_data) will not
be freed by kill_bdev, and subsequently that bh will be leaked.

If blocksizes differ, sb_set_blocksize() will kill current buffers and
page cache by using kill_bdev(). And then super block will be reread
again but using correct blocksize this time. sb_set_blocksize() didn't
fully free superblock page and buffer head, and being busy, they were
not freed and instead leaked.

This can easily be reproduced by calling an infinite loop of:

systemctl start <ext4_on_lvm>.mount, and
systemctl stop <ext4_on_lvm>.mount

... since systemd creates a cgroup for each slice which it mounts, and
the bh leak get amplified by a dying memory cgroup that also never
gets freed, and memory consumption is much more easily noticed.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Ubuntu USN Ubuntu USN USN-7415-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7428-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7428-2 Linux kernel (FIPS) vulnerabilities
Ubuntu USN Ubuntu USN USN-7429-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7429-2 Linux kernel (FIPS) vulnerabilities
Ubuntu USN Ubuntu USN USN-7461-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7461-2 Linux kernel (FIPS) vulnerabilities
Ubuntu USN Ubuntu USN USN-7461-3 Linux kernel (Xilinx ZynqMP) vulnerabilities
Ubuntu USN Ubuntu USN USN-7462-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7462-2 Linux kernel (AWS FIPS) vulnerabilities
Ubuntu USN Ubuntu USN USN-7463-1 Linux kernel (IBM) vulnerabilities
Ubuntu USN Ubuntu USN USN-7539-1 Linux kernel (Raspberry Pi) vulnerabilities
Ubuntu USN Ubuntu USN USN-7540-1 Linux kernel (Raspberry Pi) vulnerabilities
History
Type Values Removed Values Added
First Time appeared Linux
Linux linux Kernel
Weaknesses CWE-401
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.13:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.13:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.13:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.13:rc4:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
Metrics cvssV3_1

{'score': 4.1, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H'}

cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
Linux
Published
Updated
May 11, 2026, 1:48 PM
Reserved
Mar 4, 2024, 6:12 PM
Status
Analyzed
Published
Mar 15, 2024, 9:15 PM
Modified
Jun 17, 2026, 4:16 AM
Severity
Low
Public date
Mar 15, 2024, 12:00 AM