5.5
MEDIUM
CVE-2021-47406
"Linux Kernel ext4 Unlimited Loop Vulnerability"
Description

In the Linux kernel, the following vulnerability has been resolved: ext4: add error checking to ext4_ext_replay_set_iblocks() If the call to ext4_map_blocks() fails due to an corrupted file system, ext4_ext_replay_set_iblocks() can get stuck in an infinite loop. This could be reproduced by running generic/526 with a file system that has inline_data and fast_commit enabled. The system will repeatedly log to the console: EXT4-fs warning (device dm-3): ext4_block_to_path:105: block 1074800922 > max in inode 131076 and the stack that it gets stuck in is: ext4_block_to_path+0xe3/0x130 ext4_ind_map_blocks+0x93/0x690 ext4_map_blocks+0x100/0x660 skip_hole+0x47/0x70 ext4_ext_replay_set_iblocks+0x223/0x440 ext4_fc_replay_inode+0x29e/0x3b0 ext4_fc_replay+0x278/0x550 do_one_pass+0x646/0xc10 jbd2_journal_recover+0x14a/0x270 jbd2_journal_load+0xc4/0x150 ext4_load_journal+0x1f3/0x490 ext4_fill_super+0x22d4/0x2c00 With this patch, generic/526 still fails, but system is no longer locking up in a tight loop. It's likely the root casue is that fast_commit replay is corrupting file systems with inline_data, and we probably need to add better error handling in the fast commit replay code path beyond what is done here, which essentially just breaks the infinite loop without reporting the to the higher levels of the code.

INFO

Published Date :

May 21, 2024, 3:15 p.m.

Last Modified :

April 2, 2025, 2:51 p.m.

Source :

416baaa9-dc9f-4396-8d5f-8c081fb06d67

Remotely Exploitable :

No

Impact Score :

3.6

Exploitability Score :

1.8
Affected Products

The following products are affected by CVE-2021-47406 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Linux linux_kernel
: Total Affected Vendor : 1 | Products : 1
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-2021-47406.

URL Resource
https://git.kernel.org/stable/c/1fd95c05d8f742abfe906620780aee4dbe1a2db0 Patch
https://git.kernel.org/stable/c/27e10c5d31ff1d222c7f797f1ee96d422859ba67 Patch
https://git.kernel.org/stable/c/a63474dbf692dd09b50fed592bc41f6de5f102fc Patch
https://git.kernel.org/stable/c/1fd95c05d8f742abfe906620780aee4dbe1a2db0 Patch
https://git.kernel.org/stable/c/27e10c5d31ff1d222c7f797f1ee96d422859ba67 Patch
https://git.kernel.org/stable/c/a63474dbf692dd09b50fed592bc41f6de5f102fc Patch

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).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2021-47406 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2021-47406 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]

    Apr. 02, 2025

    Action Type Old Value New Value
    Added CWE CWE-835
    Added CPE Configuration OR *cpe:2.3:o:linux:linux_kernel:5.15:rc2:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:5.15:rc3:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:5.15:rc1:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.10 up to (excluding) 5.10.71 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.11 up to (excluding) 5.14.10
    Added Reference Type CVE: https://git.kernel.org/stable/c/1fd95c05d8f742abfe906620780aee4dbe1a2db0 Types: Patch
    Added Reference Type kernel.org: https://git.kernel.org/stable/c/1fd95c05d8f742abfe906620780aee4dbe1a2db0 Types: Patch
    Added Reference Type CVE: https://git.kernel.org/stable/c/27e10c5d31ff1d222c7f797f1ee96d422859ba67 Types: Patch
    Added Reference Type kernel.org: https://git.kernel.org/stable/c/27e10c5d31ff1d222c7f797f1ee96d422859ba67 Types: Patch
    Added Reference Type CVE: https://git.kernel.org/stable/c/a63474dbf692dd09b50fed592bc41f6de5f102fc Types: Patch
    Added Reference Type kernel.org: https://git.kernel.org/stable/c/a63474dbf692dd09b50fed592bc41f6de5f102fc Types: 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/1fd95c05d8f742abfe906620780aee4dbe1a2db0
    Added Reference https://git.kernel.org/stable/c/27e10c5d31ff1d222c7f797f1ee96d422859ba67
    Added Reference https://git.kernel.org/stable/c/a63474dbf692dd09b50fed592bc41f6de5f102fc
  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Nov. 01, 2024

    Action Type Old Value New Value
    Added CVSS V3.1 CISA-ADP AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
  • CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    May. 28, 2024

    Action Type Old Value New Value
  • CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    May. 21, 2024

    Action Type Old Value New Value
    Added Description In the Linux kernel, the following vulnerability has been resolved: ext4: add error checking to ext4_ext_replay_set_iblocks() If the call to ext4_map_blocks() fails due to an corrupted file system, ext4_ext_replay_set_iblocks() can get stuck in an infinite loop. This could be reproduced by running generic/526 with a file system that has inline_data and fast_commit enabled. The system will repeatedly log to the console: EXT4-fs warning (device dm-3): ext4_block_to_path:105: block 1074800922 > max in inode 131076 and the stack that it gets stuck in is: ext4_block_to_path+0xe3/0x130 ext4_ind_map_blocks+0x93/0x690 ext4_map_blocks+0x100/0x660 skip_hole+0x47/0x70 ext4_ext_replay_set_iblocks+0x223/0x440 ext4_fc_replay_inode+0x29e/0x3b0 ext4_fc_replay+0x278/0x550 do_one_pass+0x646/0xc10 jbd2_journal_recover+0x14a/0x270 jbd2_journal_load+0xc4/0x150 ext4_load_journal+0x1f3/0x490 ext4_fill_super+0x22d4/0x2c00 With this patch, generic/526 still fails, but system is no longer locking up in a tight loop. It's likely the root casue is that fast_commit replay is corrupting file systems with inline_data, and we probably need to add better error handling in the fast commit replay code path beyond what is done here, which essentially just breaks the infinite loop without reporting the to the higher levels of the code.
    Added Reference kernel.org https://git.kernel.org/stable/c/a63474dbf692dd09b50fed592bc41f6de5f102fc [No types assigned]
    Added Reference kernel.org https://git.kernel.org/stable/c/27e10c5d31ff1d222c7f797f1ee96d422859ba67 [No types assigned]
    Added Reference kernel.org https://git.kernel.org/stable/c/1fd95c05d8f742abfe906620780aee4dbe1a2db0 [No types assigned]
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2021-47406 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-2021-47406 weaknesses.

CVSS31 - Vulnerability Scoring System
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality
Integrity
Availability
:
© cvefeed.io
Latest DB Update: May. 15, 2025 3:47