CriticalFix available
micropython — security advisory
A buffer overflow vulnerability in stm32_mw_usb_host of STMicroelectronics in versions before 3.5.1 allows an attacker to execute arbitrary code when the descriptor contains more endpoints than USBH_MAX_NUM_ENDPOINTS. The library is typically integrated when using a RTOS such as FreeRTOS on STM32 MCUs.
- Products
- micropython
- Affected versions
- 1.12-1, 1.17+ds-1.1, 1.17+ds-1.1ubuntu2, 1.17+ds-1ubuntu1, 1.19.1+ds-1, 1.22.1+ds-1, 1.22.1+ds-1build1, 1.22.1+ds-1build2, 1.24.1+ds-1, 1.25.0+ds-1, 1.26.1+ds-1
- Fixed versions
- 1.12-1ubuntu0.1~esm1, 1.17+ds-1.1ubuntu2+esm1, 1.22.1+ds-1ubuntu0.24.04.1~esm1
- CVEs
- CVE-2021-42553
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 00:55 UTC · Revision 1
Source evidence
A buffer overflow vulnerability in stm32_mw_usb_host of STMicroelectronics in versions before 3.5.1 allows an attacker to execute arbitrary code when the descriptor contains more endpoints than USBH_MAX_NUM_ENDPOINTS. The library is typically integrated when using a RTOS such as FreeRTOS on STM32 MCUs.
osv:UBUNTU-CVE-2021-42553
micropython
Fixed versions: 1.12-1ubuntu0.1~esm1
micropython
Fixed versions: 1.17+ds-1.1ubuntu2+esm1
micropython
Fixed versions: 1.22.1+ds-1ubuntu0.24.04.1~esm1
micropython
Fixed versions: Not specified
micropython
Fixed versions: Not specified
micropython
Fixed versions: Not specified
Complete source record
{
"id": "6d75ba468ebeb5f56d6e547e79c510a7daf6ad7d328eb1e46079067eb0266378",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2021-42553",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "UBUNTU-CVE-2021-42553",
"summary": "A buffer overflow vulnerability in stm32_mw_usb_host of STMicroelectronics in versions before 3.5.1 allows an attacker to execute arbitrary code when the descriptor contains more endpoints than USBH_MAX_NUM_ENDPOINTS. The library is typically integrated when using a RTOS such as FreeRTOS on STM32 MCUs.",
"evidence": "osv:UBUNTU-CVE-2021-42553",
"products": [
{
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"value": "micropython",
"evidence": "/affected/0/package/name"
},
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{
"value": "1.12-1ubuntu0.1~esm1",
"evidence": "/affected/0/ranges"
}
],
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{
"name": {
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"evidence": "/affected/1/versions"
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{
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"evidence": "/affected/2/versions"
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{
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{
"name": {
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{
"value": "1.26.1+ds-1",
"evidence": "/affected/4/versions"
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},
{
"name": {
"value": "micropython",
"evidence": "/affected/5/package/name"
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"prerequisites": [],
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"affected_versions": [
{
"value": "1.25.0+ds-1",
"evidence": "/affected/5/versions"
},
{
"value": "1.26.1+ds-1",
"evidence": "/affected/5/versions"
}
]
}
],
"severity": "critical",
"structured": {
"id": "UBUNTU-CVE-2021-42553",
"aliases": [
"UBUNTU-CVE-2021-42553"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
},
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
},
{
"type": "Ubuntu",
"score": "medium"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1.12-1ubuntu0.1~esm1"
}
]
}
],
"package": {
"name": "micropython",
"purl": "pkg:deb/ubuntu/micropython?arch=source&distro=esm-apps%2Ffocal",
"ecosystem": "Ubuntu:Pro:20.04:LTS"
},
"versions": [
"1.12-1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-42553.json"
},
"ecosystem_specific": {
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],
"availability": "Available with Ubuntu Pro: https://ubuntu.com/pro"
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},
{
"ranges": [
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"events": [
{
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{
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]
}
],
"package": {
"name": "micropython",
"purl": "pkg:deb/ubuntu/micropython?arch=source&distro=esm-apps%2Fjammy",
"ecosystem": "Ubuntu:Pro:22.04:LTS"
},
"versions": [
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"1.17+ds-1.1",
"1.17+ds-1.1ubuntu2"
],
"database_specific": {
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},
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],
"availability": "Available with Ubuntu Pro: https://ubuntu.com/pro"
}
},
{
"ranges": [
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{
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]
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],
"package": {
"name": "micropython",
"purl": "pkg:deb/ubuntu/micropython?arch=source&distro=esm-apps%2Fnoble",
"ecosystem": "Ubuntu:Pro:24.04:LTS"
},
"versions": [
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"1.22.1+ds-1",
"1.22.1+ds-1build1",
"1.22.1+ds-1build2"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-42553.json"
},
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"package": {
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"ecosystem": "Ubuntu:25.10"
},
"versions": [
"1.24.1+ds-1",
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"database_specific": {
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"ecosystem": "Ubuntu:26.04:LTS"
},
"versions": [
"1.25.0+ds-1",
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"database_specific": {
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},
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],
"modified": "2026-10-17T12:56:15.860718811Z",
"provider": "osv",
"upstream": [
"CVE-2021-42553"
],
"references": [
"https://ubuntu.com/security/CVE-2021-42553",
"https://github.com/STMicroelectronics/stm32_mw_usb_host/pull/4",
"https://www.cve.org/CVERecord?id=CVE-2021-42553",
"https://ubuntu.com/security/notices/USN-7472-1"
]
},
"related_cves": [
{
"value": "CVE-2021-42553",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/1/score"
},
"source_id": "core-osv",
"document_id": 355075,
"published_at": "2022-10-21T10:15:00+00:00"
}