CVE-2025-22036

exfat: fix random stack corruption after get_block

Published Apr 16, 2025 CVSS 3.1 · 7.8 High EPSS < 1% KEV · Not listed
Description
In the Linux kernel, the following vulnerability has been resolved:

exfat: fix random stack corruption after get_block

When get_block is called with a buffer_head allocated on the stack, such
as do_mpage_readpage, stack corruption due to buffer_head UAF may occur in
the following race condition situation.

<CPU 0> <CPU 1>
mpage_read_folio
<<bh on stack>>
do_mpage_readpage
exfat_get_block
bh_read
__bh_read
get_bh(bh)
submit_bh
wait_on_buffer
...
end_buffer_read_sync
__end_buffer_read_notouch
unlock_buffer
<<keep going>>
...
...
...
...
<<bh is not valid out of mpage_read_folio>>
.
.
another_function
<<variable A on stack>>
put_bh(bh)
atomic_dec(bh->b_count)
* stack corruption here *

This patch returns -EAGAIN if a folio does not have buffers when bh_read
needs to be called. By doing this, the caller can fallback to functions
like block_read_full_folio(), create a buffer_head in the folio, and then
call get_block again.

Let's do not call bh_read() with on-stack buffer_head.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
EUVD EUVD EUVD-2025-11260 In the Linux kernel, the following vulnerability has been resolved: exfat: fix random stack corruption after get_block When get_block is called with a buffer_head allocated on the stack, such as do_mpage_readpage, stack corruption due to buffer_head UAF may occur in the following race condition situation. <CPU 0> <CPU 1> mpage_read_folio <<bh on stack>> do_mpage_readpage exfat_get_block bh_read __bh_read get_bh(bh) submit_bh wait_on_buffer ... end_buffer_read_sync __end_buffer_read_notouch unlock_buffer <<keep going>> ... ... ... ... <<bh is not valid out of mpage_read_folio>> . . another_function <<variable A on stack>> put_bh(bh) atomic_dec(bh->b_count) * stack corruption here * This patch returns -EAGAIN if a folio does not have buffers when bh_read needs to be called. By doing this, the caller can fallback to functions like block_read_full_folio(), create a buffer_head in the folio, and then call get_block again. Let's do not call bh_read() with on-stack buffer_head.
Ubuntu USN Ubuntu USN USN-7594-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7594-2 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-7594-3 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7835-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7835-2 Linux kernel (Real-time) vulnerabilities
Ubuntu USN Ubuntu USN USN-7835-3 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7835-4 Linux kernel (HWE) vulnerabilities
Ubuntu USN Ubuntu USN USN-7835-5 Linux kernel (Oracle) vulnerabilities
Ubuntu USN Ubuntu USN USN-7835-6 Linux kernel (AWS) vulnerabilities
Ubuntu USN Ubuntu USN USN-7887-1 Linux kernel (Raspberry Pi Real-time) vulnerabilities
Ubuntu USN Ubuntu USN USN-7887-2 Linux kernel (Raspberry Pi) vulnerabilities
Ubuntu USN Ubuntu USN USN-7940-1 Linux kernel (Azure FIPS) vulnerabilities
Ubuntu USN Ubuntu USN USN-7940-2 Linux kernel (Azure, N-Series) vulnerabilities
History
Type Values Removed Values Added
Metrics cvssV3_1

{'score': 7, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'}

cvssV3_1

{'score': 7.8, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'}

Type Values Removed Values Added
Metrics ssvc

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

Type Values Removed Values Added
Metrics threat_severity

Moderate

threat_severity

Important

Type Values Removed Values Added
First Time appeared Linux
Linux linux Kernel
Weaknesses CWE-362
CWE-416
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
Metrics 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'}

cvssV3_1

{'score': 7.0, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'}

Type Values Removed Values Added
References
Metrics threat_severity

None

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'}

threat_severity

Moderate

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: exfat: fix random stack corruption after get_block When get_block is called with a buffer_head allocated on the stack, such as do_mpage_readpage, stack corruption due to buffer_head UAF may occur in the following race condition situation. <CPU 0> <CPU 1> mpage_read_folio <<bh on stack>> do_mpage_readpage exfat_get_block bh_read __bh_read get_bh(bh) submit_bh wait_on_buffer ... end_buffer_read_sync __end_buffer_read_notouch unlock_buffer <<keep going>> ... ... ... ... <<bh is not valid out of mpage_read_folio>> . . another_function <<variable A on stack>> put_bh(bh) atomic_dec(bh->b_count) * stack corruption here * This patch returns -EAGAIN if a folio does not have buffers when bh_read needs to be called. By doing this, the caller can fallback to functions like block_read_full_folio(), create a buffer_head in the folio, and then call get_block again. Let's do not call bh_read() with on-stack buffer_head.
Title exfat: fix random stack corruption after get_block
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
Linux
Published
Updated
Aug 5, 2026, 11:56 AM
Reserved
Dec 29, 2024, 8:45 AM
Status
Modified
Published
Apr 16, 2025, 3:15 PM
Modified
Jul 30, 2026, 6:22 AM
Severity
Important
Public date
Apr 16, 2025, 12:00 AM