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CVE-2021-47007

5.5 · MEDIUM

In the Linux kernel, the following vulnerability has been resolved: f2fs: fix panic during f2fs_resize_fs() f2fs_resize_fs() hangs in below callstack with testcase: - mkfs 16GB image & mount imag…

Published Feb 28, 2024CWE-754EPSS 0.24%

Overview

CVE-2021-47007 is a medium-severity vulnerability. It was published on February 28, 2024 and has a CVSS 3.1 base score of 5.5 (MEDIUM).

This vulnerability has a CVSS 3.1 base score of 5.5, rated MEDIUM. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.

Technical description

In the Linux kernel, the following vulnerability has been resolved:

f2fs: fix panic during f2fs_resize_fs()

f2fs_resize_fs() hangs in below callstack with testcase:

- mkfs 16GB image & mount image

- dd 8GB fileA

- dd 8GB fileB

- sync

- rm fileA

- sync

- resize filesystem to 8GB

kernel BUG at segment.c:2484!

Call Trace:

allocate_segment_by_default+0x92/0xf0 [f2fs]

f2fs_allocate_data_block+0x44b/0x7e0 [f2fs]

do_write_page+0x5a/0x110 [f2fs]

f2fs_outplace_write_data+0x55/0x100 [f2fs]

f2fs_do_write_data_page+0x392/0x850 [f2fs]

move_data_page+0x233/0x320 [f2fs]

do_garbage_collect+0x14d9/0x1660 [f2fs]

free_segment_range+0x1f7/0x310 [f2fs]

f2fs_resize_fs+0x118/0x330 [f2fs]

__f2fs_ioctl+0x487/0x3680 [f2fs]

__x64_sys_ioctl+0x8e/0xd0

do_syscall_64+0x33/0x80

entry_SYSCALL_64_after_hwframe+0x44/0xa9

The root cause is we forgot to check that whether we have enough space

in resized filesystem to store all valid blocks in before-resizing

filesystem, then allocator will run out-of-spac

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References

Refgit.kernel.org/stable/c/1c20a4896409f5ca1c770e1880c33d0a28a8b10fRefgit.kernel.org/stable/c/3ab0598e6d860ef49d029943ba80f627c15c15d6Refgit.kernel.org/stable/c/822054e5026c43b1dd60cf387dd999e95ee2ecc2Refgit.kernel.org/stable/c/860afd680d9cc1dabd61cda3cd246f60aa1eb705Refgit.kernel.org/stable/c/1c20a4896409f5ca1c770e1880c33d0a28a8b10fRefgit.kernel.org/stable/c/3ab0598e6d860ef49d029943ba80f627c15c15d6Refgit.kernel.org/stable/c/822054e5026c43b1dd60cf387dd999e95ee2ecc2Refgit.kernel.org/stable/c/860afd680d9cc1dabd61cda3cd246f60aa1eb705

How CyberStrike helps

Frequently asked questions

What is CVE-2021-47007?

CVE-2021-47007 is a medium-severity vulnerability. It was published on February 28, 2024 and has a CVSS 3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2021-47007?

This vulnerability has a CVSS 3.1 base score of 5.5, rated MEDIUM. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.

How do I fix or remediate CVE-2021-47007?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2021-47007?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2021-47007 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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