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CVE-2024-8946

MicroPython VFS Unmount vfs.c mp_vfs_umount heap-based overflow

6.9 MediumFix available

A vulnerability was found in MicroPython 1.23.0. It has been classified as critical. Affected is the function mp_vfs_umount of the file extmod/vfs.c of the component VFS Unmount Handler. The manipulation leads to heap-based buffer overflow. It is possible to launch the attack remotely. The exploit has been disclosed to the public and may be used. The name of the patch is 29943546343c92334e8518695a11fc0e2ceea68b. It is recommended to apply a patch to fix this issue. In the VFS unmount process, the comparison between the mounted path string and the unmount requested string is based solely on the length of the unmount string, which can lead to a heap buffer overflow read.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
Low
Integrity
Low
Availability
Low

Exploit likelihood

1.01%Up 1.0 points since Sep 18, 2024
90%50%10%1%

What each source reports

CVE List Score used 6.9

MicroPython VFS Unmount vfs.c mp_vfs_umount heap-based overflow

A vulnerability was found in MicroPython 1.23.0. It has been classified as critical. Affected is the function mp_vfs_umount of the file extmod/vfs.c of the component VFS Unmount Handler. The manipulation leads to heap-based buffer overflow. It is possible to launch the attack remotely. The exploit has been disclosed to the public and may be used. The name of the patch is 29943546343c92334e8518695a11fc0e2ceea68b. It is recommended to apply a patch to fix this issue. In the VFS unmount process, the comparison between the mounted path string and the unmount requested string is based solely on the length of the unmount string, which can lead to a heap buffer overflow read.

Record
CVE-2024-8946
CVSS 4.0
6.9 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N
CVSS 3.1
7.3 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
CVSS 3.0
7.3 HighCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
CVSS 2.0
7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P
Weakness
CWE-122
Updated
2026-11-02
EUVDEUVD-2024-0102 6.9

A vulnerability was found in MicroPython 1.23.0. It has been classified as critical. Affected is the function mp_vfs_umount of the file extmod/vfs.c of the component VFS Unmount Handler. The manipulation leads to heap-based buffer overflow. It is possible to launch the attack remotely. The exploit has been disclosed to the public and may be used. The name of the patch is 29943546343c92334e8518695a11fc0e2ceea68b. It is recommended to apply a patch to fix this issue. In the VFS unmount process, the comparison between the mounted path string and the unmount requested string is based solely on the length of the unmount string, which can lead to a heap buffer overflow read.

Record
EUVD-2024-0102
CVSS 4.0
6.9 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N
Updated
2026-11-03
GitHub AdvisoriesGHSA-74qm-4v7r-jw2f 6.9

Heap-based Buffer Overflow in MicroPython

A vulnerability was found in MicroPython 1.23.0. It has been classified as critical. Affected is the function mp_vfs_umount of the file extmod/vfs.c of the component VFS Unmount Handler. The manipulation leads to heap-based buffer overflow. It is possible to launch the attack remotely. The exploit has been disclosed to the public and may be used. The name of the patch is 29943546343c92334e8518695a11fc0e2ceea68b. It is recommended to apply a patch to fix this issue. In the VFS unmount process, the comparison between the mounted path string and the unmount requested string is based solely on the length of the unmount string, which can lead to a heap buffer overflow read.

Record
GHSA-74qm-4v7r-jw2f
CVSS 4.0
6.9 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1
7.3 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
Weakness
CWE-122, CWE-787
Updated
2026-11-02
NVD 6.9

A vulnerability was found in MicroPython 1.23.0. It has been classified as critical. Affected is the function mp_vfs_umount of the file extmod/vfs.c of the component VFS Unmount Handler. The manipulation leads to heap-based buffer overflow. It is possible to launch the attack remotely. The exploit has been disclosed to the public and may be used. The name of the patch is 29943546343c92334e8518695a11fc0e2ceea68b. It is recommended to apply a patch to fix this issue. In the VFS unmount process, the comparison between the mounted path string and the unmount requested string is based solely on the length of the unmount string, which can lead to a heap buffer overflow read.

Record
CVE-2024-8946
CVSS 4.0
6.9 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1
7.3 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS 2.0
7.5 HighAV:N/AC:L/Au:N/C:P/I:P/A:P
Weakness
CWE-122, CWE-787
Updated
2026-11-02
OSV 6.9

MicroPython VFS Unmount vfs.c mp_vfs_umount heap-based overflow

A vulnerability was found in MicroPython 1.23.0. It has been classified as critical. Affected is the function mp_vfs_umount of the file extmod/vfs.c of the component VFS Unmount Handler. The manipulation leads to heap-based buffer overflow. It is possible to launch the attack remotely. The exploit has been disclosed to the public and may be used. The name of the patch is 29943546343c92334e8518695a11fc0e2ceea68b. It is recommended to apply a patch to fix this issue. In the VFS unmount process, the comparison between the mounted path string and the unmount requested string is based solely on the length of the unmount string, which can lead to a heap buffer overflow read.

Record
CVE-2024-8946
CVSS 4.0
6.9 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N
Weakness
CWE-122
Updated
2026-11-02
OSVDEBIAN-CVE-2024-8946 7.5

A vulnerability was found in MicroPython 1.23.0. It has been classified as critical. Affected is the function mp_vfs_umount of the file extmod/vfs.c of the component VFS Unmount Handler. The manipulation leads to heap-based buffer overflow. It is possible to launch the attack remotely. The exploit has been disclosed to the public and may be used. The name of the patch is 29943546343c92334e8518695a11fc0e2ceea68b. It is recommended to apply a patch to fix this issue. In the VFS unmount process, the comparison between the mounted path string and the unmount requested string is based solely on the length of the unmount string, which can lead to a heap buffer overflow read.

Record
DEBIAN-CVE-2024-8946
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
Show 7 moreShow less
OSVGHSA-74qm-4v7r-jw2f 6.9

Heap-based Buffer Overflow in MicroPython

A vulnerability was found in MicroPython 1.23.0. It has been classified as critical. Affected is the function mp_vfs_umount of the file extmod/vfs.c of the component VFS Unmount Handler. The manipulation leads to heap-based buffer overflow. It is possible to launch the attack remotely. The exploit has been disclosed to the public and may be used. The name of the patch is 29943546343c92334e8518695a11fc0e2ceea68b. It is recommended to apply a patch to fix this issue. In the VFS unmount process, the comparison between the mounted path string and the unmount requested string is based solely on the length of the unmount string, which can lead to a heap buffer overflow read.

Record
GHSA-74qm-4v7r-jw2f
CVSS 4.0
6.9 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1
7.3 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
Weakness
CWE-122, CWE-787
Updated
2026-11-02
OSVPYSEC-2024-91 7.5

A vulnerability was found in MicroPython 1.23.0. It has been classified as critical. Affected is the function mp_vfs_umount of the file extmod/vfs.c of the component VFS Unmount Handler. The manipulation leads to heap-based buffer overflow. It is possible to launch the attack remotely. The exploit has been disclosed to the public and may be used. The name of the patch is 29943546343c92334e8518695a11fc0e2ceea68b. It is recommended to apply a patch to fix this issue. In the VFS unmount process, the comparison between the mounted path string and the unmount requested string is based solely on the length of the unmount string, which can lead to a heap buffer overflow read.

Record
PYSEC-2024-91
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVPYSEC-2024-93 7.5

A vulnerability was found in MicroPython 1.23.0. It has been classified as critical. Affected is the function mp_vfs_umount of the file extmod/vfs.c of the component VFS Unmount Handler. The manipulation leads to heap-based buffer overflow. It is possible to launch the attack remotely. The exploit has been disclosed to the public and may be used. The name of the patch is 29943546343c92334e8518695a11fc0e2ceea68b. It is recommended to apply a patch to fix this issue. In the VFS unmount process, the comparison between the mounted path string and the unmount requested string is based solely on the length of the unmount string, which can lead to a heap buffer overflow read.

Record
PYSEC-2024-93
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVPYSEC-2024-95 7.5

A vulnerability was found in MicroPython 1.23.0. It has been classified as critical. Affected is the function mp_vfs_umount of the file extmod/vfs.c of the component VFS Unmount Handler. The manipulation leads to heap-based buffer overflow. It is possible to launch the attack remotely. The exploit has been disclosed to the public and may be used. The name of the patch is 29943546343c92334e8518695a11fc0e2ceea68b. It is recommended to apply a patch to fix this issue. In the VFS unmount process, the comparison between the mounted path string and the unmount requested string is based solely on the length of the unmount string, which can lead to a heap buffer overflow read.

Record
PYSEC-2024-95
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVPYSEC-2024-96 7.5

A vulnerability was found in MicroPython 1.23.0. It has been classified as critical. Affected is the function mp_vfs_umount of the file extmod/vfs.c of the component VFS Unmount Handler. The manipulation leads to heap-based buffer overflow. It is possible to launch the attack remotely. The exploit has been disclosed to the public and may be used. The name of the patch is 29943546343c92334e8518695a11fc0e2ceea68b. It is recommended to apply a patch to fix this issue. In the VFS unmount process, the comparison between the mounted path string and the unmount requested string is based solely on the length of the unmount string, which can lead to a heap buffer overflow read.

Record
PYSEC-2024-96
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVUBUNTU-CVE-2024-8946 6.9

A vulnerability was found in MicroPython 1.23.0. It has been classified as critical. Affected is the function mp_vfs_umount of the file extmod/vfs.c of the component VFS Unmount Handler. The manipulation leads to heap-based buffer overflow. It is possible to launch the attack remotely. The exploit has been disclosed to the public and may be used. The name of the patch is 29943546343c92334e8518695a11fc0e2ceea68b. It is recommended to apply a patch to fix this issue. In the VFS unmount process, the comparison between the mounted path string and the unmount requested string is based solely on the length of the unmount string, which can lead to a heap buffer overflow read.

Record
UBUNTU-CVE-2024-8946
CVSS 4.0
6.9 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS 3.1
7.3 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
Updated
2026-11-02
OSVUSN-7472-1 No score

micropython vulnerabilities

Junwha Hong and Wonil Jang discovered that Micropython incorrectly handled the length of a buffer in mp_vfs_umount, leading to a heap-based buffer overflow vulnerability. If a user or automated system were tricked into opening a specially crafted file, an attacker could possibly use this issue to cause a denial of service or possibly execute arbitrary code. (CVE-2024-8946)

Junwha Hong and Wonil Jang discovered that Micropython incorrectly handled memory, leading to a use-after-free vulnerability under certain circumstances. If a user or automated system were tricked into opening a specially crafted file, an attacker could possibly use this issue to cause a denial of service or possibly execute arbitrary code. (CVE-2024-8947)

It was discovered that Middleware USB Host MCU Component incorrectly handled memory, leading to a buffer overflow vulnerability, If a user or automated system were tricked into opening a specially crafted file, an attacker could possibly use this issue to cause a denial of service or possibly execute arbitrary code. (CVE-2021-42553)

Record
USN-7472-1
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
micropython-copy
PyPI
through 3.3.3.post3 None known
micropython-io
PyPI
through 0.1 None known
micropython-os-path
PyPI
through 0.1.3 None known
micropython-string
PyPI
through 0.1 None known
micropython
Debian:13
before 1.24.0+ds-1
1.24.0+ds-1
micropython
Debian:14
before 1.24.0+ds-1
1.24.0+ds-1
micropython-copy
PyPI
through 3.3.3.post3, plus listed versions
0.0.10.0.23.3.3-2
None known
micropython-io
PyPI
through 0.1, plus listed versions
0.0.10.0.20.0.3
None known
micropython-os-path
PyPI
through 0.1.3, plus listed versions
0.0.10.0.20.0.30.10.1.10.1.2
None known
micropython-string
PyPI
through 0.1, plus listed versions
0.0.1
None known
Show 10 moreShow less
Affected packages
PackageAffectedFixed
micropython-copy
PyPI
All versions, plus listed versions
0.0.10.0.23.3.3-23.3.3.post3
None known
micropython-io
PyPI
All versions, plus listed versions
0.0.10.0.20.0.30.1
None known
micropython-os-path
PyPI
All versions, plus listed versions
0.0.10.0.20.0.30.10.1.10.1.20.1.3
None known
micropython-string
PyPI
All versions, plus listed versions
0.0.10.1v1.24.0-previewv1.23.0v1.22.0
Show 45 moreShow less
v1.23.0-previewv1.22.0-previewv1.21.0v1.20.0v1.19.1v1.19v1.18v1.17v1.16v1.15v1.14v1.13v1.12v1.11v1.10v1.9.4v1.9.3v1.9.2v1.9.1v1.9v1.8.7v1.8.6v1.8.5v1.8.4v1.8.3v1.8.2v1.8.1v1.8v1.7v1.6v1.5.2v1.5.1v1.5v1.4.6v1.4.5v1.4.4v1.4.3v1.4.2v1.4.1v1.4v1.3.10v1.3.9v1.3.8v1.3.7v1.3.6
None known
micropython
Ubuntu:Pro:20.04:LTS
before 1.12-1ubuntu0.1~esm1, plus listed versions
1.12-1
1.12-1ubuntu0.1~esm1
micropython
Ubuntu:Pro:22.04:LTS
before 1.17+ds-1.1ubuntu2+esm1, plus listed versions
1.17+ds-1ubuntu11.17+ds-1.11.17+ds-1.1ubuntu2
1.17+ds-1.1ubuntu2+esm1
micropython
Ubuntu:Pro:24.04:LTS
before 1.22.1+ds-1ubuntu0.24.04.1~esm1, plus listed versions
1.19.1+ds-11.22.1+ds-11.22.1+ds-1build11.22.1+ds-1build2
1.22.1+ds-1ubuntu0.24.04.1~esm1
micropython
Ubuntu:Pro:20.04:LTS
From an advisory covering 3 CVEs
before 1.12-1ubuntu0.1~esm1, plus listed versions
1.12-1
1.12-1ubuntu0.1~esm1
micropython
Ubuntu:Pro:22.04:LTS
From an advisory covering 3 CVEs
before 1.17+ds-1.1ubuntu2+esm1, plus listed versions
1.17+ds-1ubuntu11.17+ds-1.11.17+ds-1.1ubuntu2
1.17+ds-1.1ubuntu2+esm1
micropython
Ubuntu:Pro:24.04:LTS
From an advisory covering 3 CVEs
before 1.22.1+ds-1ubuntu0.24.04.1~esm1, plus listed versions
1.19.1+ds-11.22.1+ds-11.22.1+ds-1build11.22.1+ds-1build2
1.22.1+ds-1ubuntu0.24.04.1~esm1

History

History
RecordedChangedSources
affected, facts
aliases, publishedEUVD
first indexedCVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2024-8946 is a medium vulnerability (CVSS 6.9) in Micropython, published September 17, 2024. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.01%, the 63rd percentile. Fixed in micropython 1.24.0+ds-1.

References

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