CVE-2025-39989

Source
https://nvd.nist.gov/vuln/detail/CVE-2025-39989
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-39989.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2025-39989
Downstream
Published
2025-04-18T07:01:39Z
Modified
2025-10-16T06:38:15.870398Z
Summary
x86/mce: use is_copy_from_user() to determine copy-from-user context
Details

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

x86/mce: use iscopyfrom_user() to determine copy-from-user context

Patch series "mm/hwpoison: Fix regressions in memory failure handling", v4.

1. What am I trying to do:

This patchset resolves two critical regressions related to memory failure handling that have appeared in the upstream kernel since version 5.17, as compared to 5.10 LTS.

- copyin case: poison found in user page while kernel copying from user space
- instr case: poison found while instruction fetching in user space

2. What is the expected outcome and why

  • For copyin case:

Kernel can recover from poison found where kernel is doing getuser() or copyfromuser() if those places get an error return and the kernel return -EFAULT to the process instead of crashing. More specifily, MCE handler checks the fixup handler type to decide whether an in kernel #MC can be recovered. When EXTYPEUACCESS is found, the PC jumps to recovery code specified in _ASMEXTABLE_FAULT() and return a -EFAULT to user space.

  • For instr case:

If a poison found while instruction fetching in user space, full recovery is possible. User process takes #PF, Linux allocates a new page and fills by reading from storage.

3. What actually happens and why

  • For copyin case: kernel panic since v5.17

Commit 4c132d1d844a ("x86/futex: Remove .fixup usage") introduced a new extable fixup type, EXTYPEEFAULTREG, and later patches updated the extable fixup type for copy-from-user operations, changing it from EXTYPEUACCESS to EXTYPEEFAULTREG. It breaks previous EXTYPEUACCESS handling when posion found in getuser() or copyfrom_user().

  • For instr case: user process is killed by a SIGBUS signal due to #CMCI and #MCE race

When an uncorrected memory error is consumed there is a race between the CMCI from the memory controller reporting an uncorrected error with a UCNA signature, and the core reporting and SRAR signature machine check when the data is about to be consumed.

Background: why UNcorrected errors tied to CMCI in Intel platform [1]

Prior to Icelake memory controllers reported patrol scrub events that detected a previously unseen uncorrected error in memory by signaling a broadcast machine check with an SRAO (Software Recoverable Action Optional) signature in the machine check bank. This was overkill because it's not an urgent problem that no core is on the verge of consuming that bad data. It's also found that multi SRAO UCE may cause nested MCE interrupts and finally become an IERR.

Hence, Intel downgrades the machine check bank signature of patrol scrub from SRAO to UCNA (Uncorrected, No Action required), and signal changed to

CMCI. Just to add to the confusion, Linux does take an action (in

ucdecodenotifier()) to try to offline the page despite the UCNA signature name.

Background: why #CMCI and #MCE race when poison is consuming in

Intel platform [1]

Having decided that CMCI/UCNA is the best action for patrol scrub errors, the memory controller uses it for reads too. But the memory controller is executing asynchronously from the core, and can't tell the difference between a "real" read and a speculative read. So it will do CMCI/UCNA if an error is found in any read.

Thus:

1) Core is clever and thinks address A is needed soon, issues a speculative read.

2) Core finds it is going to use address A soon after sending the read request

3) The CMCI from the memory controller is in a race with MCE from the core that will soon try to retire the load from address A.

Quite often (because speculation has got better) the CMCI from the memory controller is delivered before the core is committed to the instruction reading address A, so the interrupt is taken, and Linux offlines the page (marking it as poison).

Why user process is killed for instr case

Commit 046545a661af ("mm/hwpoison: fix error page recovered but reported "not ---truncated---

References

Affected packages

Git / git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

Affected ranges

Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
4c132d1d844a53fc4e4b5c34e36ef10d6124b783
Fixed
5724654a084f701dc64b08d34a0e800f22f0e6e4
Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
4c132d1d844a53fc4e4b5c34e36ef10d6124b783
Fixed
3e3d8169c0950a0b3cd5105f6403a78350dcac80
Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
4c132d1d844a53fc4e4b5c34e36ef10d6124b783
Fixed
449413da90a337f343cc5a73070cbd68e92e8a54
Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
4c132d1d844a53fc4e4b5c34e36ef10d6124b783
Fixed
0b8388e97ba6a8c033f9a8b5565af41af07f9345
Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
4c132d1d844a53fc4e4b5c34e36ef10d6124b783
Fixed
1a15bb8303b6b104e78028b6c68f76a0d4562134
Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
88eded8104d2ca0429703755dd250f8cbecc1447

Affected versions

v4.*

v4.19.1
v4.19.10
v4.19.11
v4.19.12
v4.19.13
v4.19.14
v4.19.15
v4.19.16
v4.19.17
v4.19.18
v4.19.19
v4.19.2
v4.19.20
v4.19.21
v4.19.22
v4.19.23
v4.19.24
v4.19.25
v4.19.26
v4.19.27
v4.19.28
v4.19.29
v4.19.3
v4.19.30
v4.19.31
v4.19.32
v4.19.33
v4.19.34
v4.19.35
v4.19.36
v4.19.37
v4.19.38
v4.19.39
v4.19.4
v4.19.40
v4.19.41
v4.19.42
v4.19.43
v4.19.44
v4.19.45
v4.19.46
v4.19.47
v4.19.48
v4.19.49
v4.19.5
v4.19.50
v4.19.51
v4.19.52
v4.19.53
v4.19.54
v4.19.55
v4.19.56
v4.19.57
v4.19.58
v4.19.59
v4.19.6
v4.19.60
v4.19.61
v4.19.62
v4.19.63
v4.19.64
v4.19.65
v4.19.66
v4.19.67
v4.19.68
v4.19.69
v4.19.7
v4.19.70
v4.19.71
v4.19.72
v4.19.73
v4.19.74
v4.19.75
v4.19.76
v4.19.77
v4.19.78
v4.19.79
v4.19.8
v4.19.80
v4.19.81
v4.19.82
v4.19.83
v4.19.84
v4.19.85
v4.19.86
v4.19.87
v4.19.88
v4.19.89
v4.19.9

v5.*

v5.10.1
v5.10.10
v5.10.11
v5.10.12
v5.10.13
v5.10.14
v5.10.15
v5.10.16
v5.10.17
v5.10.18
v5.10.19
v5.10.2
v5.10.20
v5.10.21
v5.10.22
v5.10.23
v5.10.24
v5.10.25
v5.10.26
v5.10.27
v5.10.28
v5.10.29
v5.10.3
v5.10.30
v5.10.31
v5.10.32
v5.10.33
v5.10.34
v5.10.35
v5.10.36
v5.10.37
v5.10.38
v5.10.39
v5.10.4
v5.10.40
v5.10.41
v5.10.42
v5.10.43
v5.10.44
v5.10.45
v5.10.46
v5.10.47
v5.10.48
v5.10.49
v5.10.5
v5.10.50
v5.10.51
v5.10.52
v5.10.53
v5.10.54
v5.10.55
v5.10.56
v5.10.57
v5.10.58
v5.10.59
v5.10.6
v5.10.60
v5.10.61
v5.10.62
v5.10.63
v5.10.64
v5.10.65
v5.10.66
v5.10.67
v5.10.68
v5.10.69
v5.10.7
v5.10.70
v5.10.71
v5.10.72
v5.10.73
v5.10.74
v5.10.75
v5.10.76
v5.10.77
v5.10.78
v5.10.79
v5.10.8
v5.10.80
v5.10.9
v5.15.100
v5.15.101
v5.15.102
v5.15.103
v5.15.104
v5.15.105
v5.15.106
v5.15.107
v5.15.108
v5.15.109
v5.15.110
v5.15.111
v5.15.112
v5.15.113
v5.15.114
v5.15.115
v5.15.116
v5.15.117
v5.15.118
v5.15.119
v5.15.120
v5.15.121
v5.15.122
v5.15.123
v5.15.124
v5.15.125
v5.15.126
v5.15.127
v5.15.128
v5.15.129
v5.15.130
v5.15.131
v5.15.132
v5.15.133
v5.15.134
v5.15.135
v5.15.136
v5.15.137
v5.15.138
v5.15.139
v5.15.140
v5.15.141
v5.15.142
v5.15.143
v5.15.144
v5.15.145
v5.15.146
v5.15.147
v5.15.148
v5.15.149
v5.15.150
v5.15.151
v5.15.152
v5.15.153
v5.15.154
v5.15.155
v5.15.156
v5.15.157
v5.15.158
v5.15.159
v5.15.160
v5.15.161
v5.15.162
v5.15.163
v5.15.164
v5.15.165
v5.15.166
v5.15.167
v5.15.168
v5.15.169
v5.15.170
v5.15.171
v5.15.172
v5.15.173
v5.15.174
v5.15.175
v5.15.176
v5.15.177
v5.15.178
v5.15.179
v5.15.180
v5.15.181
v5.15.182
v5.15.183
v5.15.184
v5.15.185
v5.15.186
v5.15.187
v5.15.188
v5.15.189
v5.15.190
v5.15.191
v5.15.192
v5.15.193
v5.15.194
v5.15.58
v5.15.59
v5.15.60
v5.15.61
v5.15.62
v5.15.63
v5.15.64
v5.15.65
v5.15.66
v5.15.67
v5.15.68
v5.15.69
v5.15.70
v5.15.71
v5.15.72
v5.15.73
v5.15.74
v5.15.75
v5.15.76
v5.15.77
v5.15.78
v5.15.79
v5.15.80
v5.15.81
v5.15.82
v5.15.83
v5.15.84
v5.15.85
v5.15.86
v5.15.87
v5.15.88
v5.15.89
v5.15.90
v5.15.91
v5.15.92
v5.15.93
v5.15.94
v5.15.95
v5.15.96
v5.15.97
v5.15.98
v5.15.99
v5.16
v5.16-rc1
v5.16-rc2
v5.16-rc3
v5.16-rc4
v5.16-rc5
v5.16-rc6
v5.16-rc7
v5.16-rc8
v5.17
v5.17-rc1
v5.17-rc2
v5.17-rc3
v5.17-rc4
v5.17-rc5
v5.17-rc6
v5.17-rc7
v5.17-rc8
v5.18
v5.18-rc1
v5.18-rc2
v5.18-rc3
v5.18-rc4
v5.18-rc5
v5.18-rc6
v5.18-rc7
v5.19
v5.19-rc1
v5.19-rc2
v5.19-rc3
v5.19-rc4
v5.19-rc5
v5.19-rc6
v5.19-rc7
v5.19-rc8
v5.4.1
v5.4.10
v5.4.11
v5.4.12
v5.4.13
v5.4.14
v5.4.15
v5.4.16
v5.4.17
v5.4.18
v5.4.19
v5.4.2
v5.4.20
v5.4.21
v5.4.22
v5.4.23
v5.4.24
v5.4.25
v5.4.26
v5.4.27
v5.4.28
v5.4.29
v5.4.3
v5.4.30
v5.4.31
v5.4.32
v5.4.33
v5.4.34
v5.4.35
v5.4.36
v5.4.37
v5.4.38
v5.4.39
v5.4.4
v5.4.40
v5.4.41
v5.4.42
v5.4.43
v5.4.44
v5.4.45
v5.4.46
v5.4.47
v5.4.48
v5.4.49
v5.4.5
v5.4.50
v5.4.51
v5.4.52
v5.4.53
v5.4.54
v5.4.55
v5.4.56
v5.4.57
v5.4.58
v5.4.59
v5.4.6
v5.4.60
v5.4.61
v5.4.62
v5.4.63
v5.4.64
v5.4.65
v5.4.66
v5.4.67
v5.4.68
v5.4.69
v5.4.7
v5.4.70
v5.4.71
v5.4.72
v5.4.73
v5.4.74
v5.4.75
v5.4.76
v5.4.77
v5.4.78
v5.4.79
v5.4.8
v5.4.80
v5.4.81
v5.4.82
v5.4.83
v5.4.84
v5.4.85
v5.4.9

v6.*

v6.0
v6.0-rc1
v6.0-rc2
v6.0-rc3
v6.0-rc4
v6.0-rc5
v6.0-rc6
v6.0-rc7
v6.1
v6.1-rc1
v6.1-rc2
v6.1-rc3
v6.1-rc4
v6.1-rc5
v6.1-rc6
v6.1-rc7
v6.1-rc8
v6.1.1
v6.1.10
v6.1.11
v6.1.12
v6.1.13
v6.1.14
v6.1.15
v6.1.16
v6.1.17
v6.1.18
v6.1.19
v6.1.2
v6.1.20
v6.1.21
v6.1.22
v6.1.23
v6.1.24
v6.1.25
v6.1.26
v6.1.27
v6.1.28
v6.1.29
v6.1.3
v6.1.30
v6.1.31
v6.1.32
v6.1.33
v6.1.34
v6.1.35
v6.1.36
v6.1.37
v6.1.38
v6.1.39
v6.1.4
v6.1.40
v6.1.41
v6.1.42
v6.1.43
v6.1.44
v6.1.45
v6.1.46
v6.1.47
v6.1.48
v6.1.49
v6.1.5
v6.1.50
v6.1.51
v6.1.52
v6.1.53
v6.1.54
v6.1.55
v6.1.56
v6.1.57
v6.1.58
v6.1.59
v6.1.6
v6.1.60
v6.1.61
v6.1.62
v6.1.63
v6.1.64
v6.1.65
v6.1.66
v6.1.67
v6.1.68
v6.1.69
v6.1.7
v6.1.70
v6.1.71
v6.1.72
v6.1.73
v6.1.74
v6.1.75
v6.1.8
v6.1.9
v6.10
v6.10-rc1
v6.10-rc2
v6.10-rc3
v6.10-rc4
v6.10-rc5
v6.10-rc6
v6.10-rc7
v6.11
v6.11-rc1
v6.11-rc2
v6.11-rc3
v6.11-rc4
v6.11-rc5
v6.11-rc6
v6.11-rc7
v6.12
v6.12-rc1
v6.12-rc2
v6.12-rc3
v6.12-rc4
v6.12-rc5
v6.12-rc6
v6.12-rc7
v6.12.1
v6.12.10
v6.12.11
v6.12.12
v6.12.13
v6.12.14
v6.12.15
v6.12.16
v6.12.17
v6.12.18
v6.12.19
v6.12.2
v6.12.20
v6.12.21
v6.12.22
v6.12.23
v6.12.24
v6.12.25
v6.12.26
v6.12.27
v6.12.28
v6.12.29
v6.12.3
v6.12.30
v6.12.31
v6.12.32
v6.12.33
v6.12.34
v6.12.35
v6.12.36
v6.12.37
v6.12.38
v6.12.39
v6.12.4
v6.12.40
v6.12.41
v6.12.42
v6.12.43
v6.12.44
v6.12.45
v6.12.46
v6.12.47
v6.12.48
v6.12.49
v6.12.5
v6.12.50
v6.12.51
v6.12.52
v6.12.53
v6.12.6
v6.12.7
v6.12.8
v6.12.9
v6.13
v6.13-rc1
v6.13-rc2
v6.13-rc3
v6.13-rc4
v6.13-rc5
v6.13-rc6
v6.13-rc7
v6.13.1
v6.13.10
v6.13.2
v6.13.3
v6.13.4
v6.13.5
v6.13.6
v6.13.7
v6.13.8
v6.13.9
v6.14
v6.14-rc1
v6.14-rc2
v6.14-rc3
v6.14-rc4
v6.14-rc5
v6.14-rc6
v6.14-rc7
v6.14.1
v6.2
v6.2-rc1
v6.2-rc2
v6.2-rc3
v6.2-rc4
v6.2-rc5
v6.2-rc6
v6.2-rc7
v6.2-rc8
v6.3
v6.3-rc1
v6.3-rc2
v6.3-rc3
v6.3-rc4
v6.3-rc5
v6.3-rc6
v6.3-rc7
v6.4
v6.4-rc1
v6.4-rc2
v6.4-rc3
v6.4-rc4
v6.4-rc5
v6.4-rc6
v6.4-rc7
v6.5
v6.5-rc1
v6.5-rc2
v6.5-rc3
v6.5-rc4
v6.5-rc5
v6.5-rc6
v6.5-rc7
v6.6
v6.6-rc1
v6.6-rc2
v6.6-rc3
v6.6-rc4
v6.6-rc5
v6.6-rc6
v6.6-rc7
v6.6.1
v6.6.10
v6.6.11
v6.6.12
v6.6.13
v6.6.14
v6.6.15
v6.6.16
v6.6.17
v6.6.18
v6.6.19
v6.6.2
v6.6.20
v6.6.21
v6.6.22
v6.6.23
v6.6.24
v6.6.25
v6.6.26
v6.6.27
v6.6.28
v6.6.29
v6.6.3
v6.6.30
v6.6.31
v6.6.32
v6.6.33
v6.6.34
v6.6.35
v6.6.36
v6.6.37
v6.6.38
v6.6.39
v6.6.4
v6.6.40
v6.6.41
v6.6.42
v6.6.43
v6.6.44
v6.6.45
v6.6.46
v6.6.47
v6.6.48
v6.6.49
v6.6.5
v6.6.50
v6.6.51
v6.6.52
v6.6.53
v6.6.54
v6.6.55
v6.6.56
v6.6.57
v6.6.58
v6.6.59
v6.6.6
v6.6.60
v6.6.61
v6.6.62
v6.6.63
v6.6.64
v6.6.65
v6.6.66
v6.6.67
v6.6.68
v6.6.69
v6.6.7
v6.6.70
v6.6.71
v6.6.72
v6.6.73
v6.6.74
v6.6.75
v6.6.76
v6.6.77
v6.6.78
v6.6.79
v6.6.8
v6.6.80
v6.6.81
v6.6.82
v6.6.83
v6.6.84
v6.6.85
v6.6.86
v6.6.87
v6.6.88
v6.6.9
v6.7
v6.7-rc1
v6.7-rc2
v6.7-rc3
v6.7-rc4
v6.7-rc5
v6.7-rc6
v6.7-rc7
v6.7-rc8
v6.8
v6.8-rc1
v6.8-rc2
v6.8-rc3
v6.8-rc4
v6.8-rc5
v6.8-rc6
v6.8-rc7
v6.9
v6.9-rc1
v6.9-rc2
v6.9-rc3
v6.9-rc4
v6.9-rc5
v6.9-rc6
v6.9-rc7

Linux / Kernel

Package

Name
Kernel

Affected ranges

Type
ECOSYSTEM
Events
Introduced
5.17.0
Fixed
6.6.89
Type
ECOSYSTEM
Events
Introduced
6.7.0
Fixed
6.12.23
Type
ECOSYSTEM
Events
Introduced
6.13.0
Fixed
6.13.11
Type
ECOSYSTEM
Events
Introduced
6.14.0
Fixed
6.14.2