CVE-2021-47119
Linux Kernel - ext4 Buffer Head Leak
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.
INFO
Published Date :
March 15, 2024, 9:15 p.m.
Last Modified :
Jan. 7, 2025, 5:31 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Update the Linux kernel to a patched version.
- Reboot the system after the update.
Public PoC/Exploit Available at Github
CVE-2021-47119 has a 1 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2021-47119.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2021-47119 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2021-47119
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Ini adalah repository kumpulan CVE v.5
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Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2021-47119 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2021-47119 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Jan. 07, 2025
Action Type Old Value New Value Added CVSS V3.1 NIST AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Added CWE NIST CWE-401 Added CPE Configuration OR *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 2.6.19 up to (excluding) 5.10.43 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.11 up to (excluding) 5.12.10 *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:*:*:*:*:*:* Changed Reference Type https://git.kernel.org/stable/c/01d349a481f0591230300a9171330136f9159bcd No Types Assigned https://git.kernel.org/stable/c/01d349a481f0591230300a9171330136f9159bcd Patch Changed Reference Type https://git.kernel.org/stable/c/01d349a481f0591230300a9171330136f9159bcd No Types Assigned https://git.kernel.org/stable/c/01d349a481f0591230300a9171330136f9159bcd Patch Changed Reference Type https://git.kernel.org/stable/c/1385b23396d511d5233b8b921ac3058b3f86a5e1 No Types Assigned https://git.kernel.org/stable/c/1385b23396d511d5233b8b921ac3058b3f86a5e1 Patch Changed Reference Type https://git.kernel.org/stable/c/1385b23396d511d5233b8b921ac3058b3f86a5e1 No Types Assigned https://git.kernel.org/stable/c/1385b23396d511d5233b8b921ac3058b3f86a5e1 Patch Changed Reference Type https://git.kernel.org/stable/c/afd09b617db3786b6ef3dc43e28fe728cfea84df No Types Assigned https://git.kernel.org/stable/c/afd09b617db3786b6ef3dc43e28fe728cfea84df Patch Changed Reference Type https://git.kernel.org/stable/c/afd09b617db3786b6ef3dc43e28fe728cfea84df No Types Assigned https://git.kernel.org/stable/c/afd09b617db3786b6ef3dc43e28fe728cfea84df Patch -
CVE Modified by af854a3a-2127-422b-91ae-364da2661108
Nov. 21, 2024
Action Type Old Value New Value Added Reference https://git.kernel.org/stable/c/01d349a481f0591230300a9171330136f9159bcd Added Reference https://git.kernel.org/stable/c/1385b23396d511d5233b8b921ac3058b3f86a5e1 Added Reference https://git.kernel.org/stable/c/afd09b617db3786b6ef3dc43e28fe728cfea84df -
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
May. 28, 2024
Action Type Old Value New Value -
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
May. 14, 2024
Action Type Old Value New Value -
CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Mar. 15, 2024
Action Type Old Value New Value Added 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. Added Reference kernel.org https://git.kernel.org/stable/c/01d349a481f0591230300a9171330136f9159bcd [No types assigned] Added Reference kernel.org https://git.kernel.org/stable/c/1385b23396d511d5233b8b921ac3058b3f86a5e1 [No types assigned] Added Reference kernel.org https://git.kernel.org/stable/c/afd09b617db3786b6ef3dc43e28fe728cfea84df [No types assigned]