Security September 2026 CVE-2026-70203
Heap-based buffer overflow in Windows Media Player allows an unauthorized attacker to execute code over a network.
Severity Critical
CVSS base score 8.8
Impact Remote Code Execution
Exploitation detected No known exploitation (MSRC assessment)
Exploitability Exploitation Less Likely
Publicly disclosed No (MSRC assessment)
EPSS · 30-day forecast 0.8% FIRST forecast dated 10 Nov 2026, for the following 30 days · FIRST percentile 57.5% · about EPSS
Customer action Required: follow the MSRC remediation guidance More details
CVSS vector CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
Public detection template No Nuclei template is listed in the current collected catalog
Component Windows Media Player
Weakness CWE-122: Heap-based Buffer Overflow
Issued by Microsoft
Last revised 8 Sep 2026 CVSS 3.1 base metrics Red raises the risk · green lowers it
Attack vector NetworkAV:N
Attack complexity LowAC:L
Privileges required NonePR:N
User interaction RequiredUI:R
Scope UnchangedS:U
Confidentiality HighC:H
Integrity HighI:H
Availability HighA:H
10 KBs KB Type Restart Applies to Known issues Other CVEs KB5122871 Security Update Required Windows Server 2025, Windows Server 2025 (Server Core installation) Resolved USB audio devices might fail to start or produce no sound All CVEs in KB5122871 KB5122876 Security Update Required Windows 10 Version 1809 for 32-bit Systems, Windows 10 Version 1809 for x64-based Systems, Windows Server 2019 and 1 more Resolved USB audio devices might fail to start or produce no sound All CVEs in KB5122876 KB5122878 Security Update Required Windows 10 Version 21H2 for 32-bit Systems, Windows 10 Version 21H2 for ARM64-based Systems, Windows 10 Version 21H2 for x64-based Systems and 3 more Resolved USB audio devices might fail to start or produce no sound All CVEs in KB5122878 KB5122880 Security Update Required Windows 11 Version 23H2 for ARM64-based Systems, Windows 11 Version 23H2 for x64-based Systems Resolved USB audio devices might fail to start or produce no sound All CVEs in KB5122880 KB5122882 Security Update Required Windows Server 2022, Windows Server 2022 (Server Core installation) Resolved USB audio devices might fail to start or produce no sound All CVEs in KB5122882 KB5123065 Monthly Rollup Required Windows Server 2012, Windows Server 2012 (Server Core installation) Resolved USB audio devices might fail to start or produce no sound All CVEs in KB5123065 KB5123066 Monthly Rollup Required Windows Server 2012 R2, Windows Server 2012 R2 (Server Core installation) Resolved USB audio devices might fail to start or produce no sound All CVEs in KB5123066 KB5123099 Security Update Required Windows 10 Version 1607 for 32-bit Systems, Windows 10 Version 1607 for x64-based Systems, Windows Server 2016 and 1 more Resolved USB audio devices might fail to start or produce no sound All CVEs in KB5123099 KB5124008 Security Update Required Windows 11 Version 24H2 for ARM64-based Systems, Windows 11 Version 24H2 for x64-based Systems, Windows 11 Version 25H2 for ARM64-based Systems and 1 more Resolved USB audio devices might fail to start or produce no sound Resolved Domain-joined devices might lose their secure trust relationship with the domain All CVEs in KB5124008 KB5124012 Security Update Required Windows 11 Version 26H1 for ARM64-based Systems, Windows 11 version 26H1 for x64-based Systems Resolved USB audio devices might fail to start or produce no sound Resolved Domain-joined devices might lose their secure trust relationship with the domain All CVEs in KB5124012
Source. This summary comes from MSRC's public CVRF document for September 2026. If the MSRC page is blocked in your browser, the NVD and CVE.org records carry the same identifier. None of this says whether your devices are affected.
Detection template: Unknown: detection-template evidence is incomplete or retained → No Nuclei template listed
6 Nov 2026 · 17:32:22 UTC Detection template: No Nuclei template listed → Unknown: detection-template evidence is incomplete or retained
6 Nov 2026 · 16:31:02 UTC Detection template: Unknown: detection-template evidence is incomplete or retained → No Nuclei template listed
2 Nov 2026 · 17:30:39 UTC Detection template: No Nuclei template listed → Unknown: detection-template evidence is incomplete or retained
2 Nov 2026 · 16:27:39 UTC Detection template: No Nuclei template listed · Customer action: Required: apply the update → Required: follow the MSRC remediation guidance · Public disclosure: No → No (MSRC assessment) · Exploitation detected: Not reported by MSRC → No known exploitation (MSRC assessment)
29 Oct 2026 Detection template: Unknown: exploit-code evidence is incomplete or retained → No Nuclei template listed · CISA KEV: Unknown: catalog evidence is incomplete or retained → Not listed in the collected catalog
23 Oct 2026 · 09:33:49 UTC Detection template: No Nuclei template listed → Unknown: exploit-code evidence is incomplete or retained · CISA KEV: Not listed in the collected catalog → Unknown: catalog evidence is incomplete or retained
23 Oct 2026 · 08:31:50 UTC
Changes are dated when recorded; day views use the last saved version from that UTC day, and citations stay fixed.
Cite this version Field-level log (61)
Up to 100 recent field edits are shown; older edits may be outside retention.
10 Nov 2026 · 18:32:11 UTC
EPSS 0.8%; scored 9 Nov 2026 → 0.8%; scored 10 Nov 2026 9 Nov 2026 · 22:24:37 UTC
EPSS 0.8%; scored 8 Nov 2026 → 0.8%; scored 9 Nov 2026 8 Nov 2026 · 15:16:05 UTC
EPSS 0.8%; scored 7 Nov 2026 → 0.8%; scored 8 Nov 2026 7 Nov 2026 · 16:12:44 UTC
EPSS 0.8%; scored 6 Nov 2026 → 0.8%; scored 7 Nov 2026 6 Nov 2026 · 19:15:37 UTC
EPSS 0.8%; scored 5 Nov 2026 → 0.8%; scored 6 Nov 2026 6 Nov 2026 · 17:32:22 UTC
Public detection template Unknown: detection-template evidence is incomplete or retained → No Nuclei template listed 6 Nov 2026 · 17:32:22 UTC
Source coverage: public-exploit-code Incomplete → Current 6 Nov 2026 · 17:32:22 UTC
Source coverage: first-epss Incomplete → Current 6 Nov 2026 · 17:32:22 UTC
Source coverage: msrc-cvrf Incomplete → Current 6 Nov 2026 · 16:31:02 UTC
Public detection template No Nuclei template listed → Unknown: detection-template evidence is incomplete or retained 6 Nov 2026 · 16:31:02 UTC
Source coverage: public-exploit-code Current → Incomplete 6 Nov 2026 · 16:31:02 UTC
Source coverage: first-epss Current → Incomplete 6 Nov 2026 · 16:31:02 UTC
Source coverage: msrc-cvrf Current → Incomplete 5 Nov 2026 · 23:42:03 UTC
EPSS 0.8%; scored 4 Nov 2026 → 0.8%; scored 5 Nov 2026 5 Nov 2026 · 02:36:20 UTC
EPSS 0.8%; scored 3 Nov 2026 → 0.8%; scored 4 Nov 2026 4 Nov 2026 · 03:04:37 UTC
EPSS 0.8%; scored 2 Nov 2026 → 0.8%; scored 3 Nov 2026 3 Nov 2026 · 01:53:36 UTC
EPSS 0.8%; scored 1 Nov 2026 → 0.8%; scored 2 Nov 2026 2 Nov 2026 · 17:30:39 UTC
Public detection template Unknown: detection-template evidence is incomplete or retained → No Nuclei template listed 2 Nov 2026 · 17:30:39 UTC
Source coverage: public-exploit-code Incomplete → Current 2 Nov 2026 · 17:30:39 UTC
Source coverage: first-epss Incomplete → Current 2 Nov 2026 · 17:30:39 UTC
Source coverage: msrc-cvrf Incomplete → Current 2 Nov 2026 · 16:27:39 UTC
Public detection template No Nuclei template listed → Unknown: detection-template evidence is incomplete or retained 2 Nov 2026 · 16:27:39 UTC
Source coverage: public-exploit-code Current → Incomplete 2 Nov 2026 · 16:27:39 UTC
Source coverage: first-epss Current → Incomplete 2 Nov 2026 · 16:27:39 UTC
Source coverage: msrc-cvrf Current → Incomplete 2 Nov 2026 · 00:36:51 UTC
EPSS 0.8%; scored 31 Oct 2026 → 0.8%; scored 1 Nov 2026 31 Oct 2026 · 18:22:15 UTC
EPSS 0.8%; scored 30 Oct 2026 → 0.8%; scored 31 Oct 2026 30 Oct 2026 · 18:02:45 UTC
EPSS 0.8%; scored 29 Oct 2026 → 0.8%; scored 30 Oct 2026 29 Oct 2026 · 20:19:26 UTC
Public detection template No Nuclei template listed 29 Oct 2026 · 20:19:26 UTC
Customer action Required: apply the update → Required: follow the MSRC remediation guidance 29 Oct 2026 · 20:19:26 UTC
Publicly disclosed No → No (MSRC assessment) 29 Oct 2026 · 20:19:26 UTC
Exploitation detected Not reported by MSRC → No known exploitation (MSRC assessment) 29 Oct 2026 · 18:33:30 UTC
EPSS 0.8%; scored 28 Oct 2026 → 0.8%; scored 29 Oct 2026 28 Oct 2026 · 20:00:33 UTC
EPSS 0.8%; scored 27 Oct 2026 → 0.8%; scored 28 Oct 2026 27 Oct 2026 · 15:48:13 UTC
EPSS 0.8%; scored 26 Oct 2026 → 0.8%; scored 27 Oct 2026 26 Oct 2026 · 23:57:09 UTC
EPSS 0.8%; scored 25 Oct 2026 → 0.8%; scored 26 Oct 2026 25 Oct 2026 · 17:12:51 UTC
EPSS 0.8%; scored 24 Oct 2026 → 0.8%; scored 25 Oct 2026 25 Oct 2026 · 01:34:18 UTC
EPSS 0.8%; scored 23 Oct 2026 → 0.8%; scored 24 Oct 2026 23 Oct 2026 · 15:51:28 UTC
EPSS 0.8%; scored 22 Oct 2026 → 0.8%; scored 23 Oct 2026 23 Oct 2026 · 09:33:49 UTC
Public exploit code Unknown: exploit-code evidence is incomplete or retained → No Nuclei template listed 23 Oct 2026 · 09:33:49 UTC
CISA KEV Unknown: catalog evidence is incomplete or retained → Not listed in the collected catalog 23 Oct 2026 · 09:33:49 UTC
Source coverage: public-exploit-code Incomplete → Current 23 Oct 2026 · 09:33:49 UTC
Source coverage: first-epss Incomplete → Current 23 Oct 2026 · 09:33:49 UTC
Source coverage: cisa-kev Incomplete → Current 23 Oct 2026 · 09:33:49 UTC
Source coverage: msrc-cvrf Incomplete → Current 23 Oct 2026 · 08:31:50 UTC
Public exploit code No Nuclei template listed → Unknown: exploit-code evidence is incomplete or retained 23 Oct 2026 · 08:31:50 UTC
CISA KEV Not listed in the collected catalog → Unknown: catalog evidence is incomplete or retained 23 Oct 2026 · 08:31:50 UTC
Source coverage: public-exploit-code Current → Incomplete 23 Oct 2026 · 08:31:50 UTC
Source coverage: first-epss Current → Incomplete 23 Oct 2026 · 08:31:50 UTC
Source coverage: cisa-kev Current → Incomplete 23 Oct 2026 · 08:31:50 UTC
Source coverage: msrc-cvrf Current → Incomplete 22 Oct 2026 · 17:33:15 UTC
EPSS 0.8%; scored 21 Oct 2026 → 0.8%; scored 22 Oct 2026 21 Oct 2026 · 21:47:24 UTC
EPSS 0.8%; scored 20 Oct 2026 → 0.8%; scored 21 Oct 2026 20 Oct 2026 · 20:53:31 UTC
EPSS 0.8%; scored 19 Oct 2026 → 0.8%; scored 20 Oct 2026 19 Oct 2026 · 15:12:40 UTC
EPSS 0.8%; scored 18 Oct 2026 → 0.8%; scored 19 Oct 2026 18 Oct 2026 · 14:54:30 UTC
EPSS 0.8%; scored 16 Oct 2026 → 0.8%; scored 18 Oct 2026 18 Oct 2026 · 14:54:30 UTC
Link: September 2026 /security?release=2026-Sep#cves 16 Oct 2026 · 16:13:25 UTC
EPSS 0.8%; scored 15 Oct 2026 → 0.8%; scored 16 Oct 2026 15 Oct 2026 · 21:30:54 UTC
EPSS 0.8%; scored 14 Oct 2026 → 0.8%; scored 15 Oct 2026 15 Oct 2026 · 01:07:54 UTC
EPSS 0.8%; scored 13 Oct 2026 → 0.8%; scored 14 Oct 2026 14 Oct 2026 · 11:22:42 UTC
Source coverage: msrc-cvrf Incomplete → Current Explore global source statements, affected packages and advisory history for CVE-2026-70203 . The catalog has a separate collection scope from Microsoft release records.
cve-program · CVE-2026-70203 Published Windows 10 Version 1607 Vendor product
Original vendor version evidence · not evaluated as a NuGet range {
"vendor": "Microsoft",
"product": "Windows 10 Version 1607",
"platforms": [
"32-bit Systems",
"x64-based Systems"
],
"versions": [
{
"version": "10.0.14393.0",
"lessThan": "10.0.14393.9512",
"versionType": "custom",
"status": "affected"
}
]
} Windows 10 Version 1809 Vendor product
Original vendor version evidence · not evaluated as a NuGet range {
"vendor": "Microsoft",
"product": "Windows 10 Version 1809",
"platforms": [
"32-bit Systems",
"x64-based Systems"
],
"versions": [
{
"version": "10.0.17763.0",
"lessThan": "10.0.17763.9245",
"versionType": "custom",
"status": "affected"
}
]
} Windows 10 Version 21H2 Vendor product
Original vendor version evidence · not evaluated as a NuGet range {
"vendor": "Microsoft",
"product": "Windows 10 Version 21H2",
"platforms": [
"32-bit Systems",
"ARM64-based Systems",
"x64-based Systems"
],
"versions": [
{
"version": "10.0.19044.0",
"lessThan": "10.0.19044.7725",
"versionType": "custom",
"status": "affected"
}
]
} Windows 10 Version 22H2 Vendor product
Original vendor version evidence · not evaluated as a NuGet range {
"vendor": "Microsoft",
"product": "Windows 10 Version 22H2",
"platforms": [
"32-bit Systems",
"ARM64-based Systems",
"x64-based Systems"
],
"versions": [
{
"version": "10.0.19045.0",
"lessThan": "10.0.19045.7725",
"versionType": "custom",
"status": "affected"
}
]
} Windows 11 version 23H2 Vendor product
Original vendor version evidence · not evaluated as a NuGet range {
"vendor": "Microsoft",
"product": "Windows 11 version 23H2",
"platforms": [
"ARM64-based Systems"
],
"versions": [
{
"version": "10.0.22631.0",
"lessThan": "10.0.22631.7582",
"versionType": "custom",
"status": "affected"
}
]
} Windows 11 Version 23H2 Vendor product
Original vendor version evidence · not evaluated as a NuGet range {
"vendor": "Microsoft",
"product": "Windows 11 Version 23H2",
"platforms": [
"x64-based Systems"
],
"versions": [
{
"version": "10.0.22631.0",
"lessThan": "10.0.22631.7582",
"versionType": "custom",
"status": "affected"
}
]
} Windows 11 Version 24H2 Vendor product
Original vendor version evidence · not evaluated as a NuGet range {
"vendor": "Microsoft",
"product": "Windows 11 Version 24H2",
"platforms": [
"ARM64-based Systems",
"x64-based Systems"
],
"versions": [
{
"version": "10.0.26100.0",
"lessThan": "10.0.26100.9445",
"versionType": "custom",
"status": "affected"
}
]
} Windows 11 Version 25H2 Vendor product
Original vendor version evidence · not evaluated as a NuGet range {
"vendor": "Microsoft",
"product": "Windows 11 Version 25H2",
"platforms": [
"ARM64-based Systems",
"x64-based Systems"
],
"versions": [
{
"version": "10.0.26200.0",
"lessThan": "10.0.26200.9445",
"versionType": "custom",
"status": "affected"
}
]
} Windows 11 version 26H1 Vendor product
Original vendor version evidence · not evaluated as a NuGet range {
"vendor": "Microsoft",
"product": "Windows 11 version 26H1",
"platforms": [
"ARM64-based Systems",
"x64-based Systems"
],
"versions": [
{
"version": "10.0.28000.0",
"lessThan": "10.0.28000.2954",
"versionType": "custom",
"status": "affected"
}
]
} Windows Server 2012 Vendor product
Original vendor version evidence · not evaluated as a NuGet range {
"vendor": "Microsoft",
"product": "Windows Server 2012",
"platforms": [
"x64-based Systems"
],
"versions": [
{
"version": "6.2.9200.0",
"lessThan": "6.2.9200.26349",
"versionType": "custom",
"status": "affected"
}
]
} Windows Server 2012 (Server Core installation) Vendor product
Original vendor version evidence · not evaluated as a NuGet range {
"vendor": "Microsoft",
"product": "Windows Server 2012 (Server Core installation)",
"platforms": [
"x64-based Systems"
],
"versions": [
{
"version": "6.2.9200.0",
"lessThan": "6.2.9200.26349",
"versionType": "custom",
"status": "affected"
}
]
} Windows Server 2012 R2 Vendor product
Original vendor version evidence · not evaluated as a NuGet range {
"vendor": "Microsoft",
"product": "Windows Server 2012 R2",
"platforms": [
"x64-based Systems"
],
"versions": [
{
"version": "6.3.9600.0",
"lessThan": "6.3.9600.23398",
"versionType": "custom",
"status": "affected"
}
]
} Windows Server 2012 R2 (Server Core installation) Vendor product
Original vendor version evidence · not evaluated as a NuGet range {
"vendor": "Microsoft",
"product": "Windows Server 2012 R2 (Server Core installation)",
"platforms": [
"x64-based Systems"
],
"versions": [
{
"version": "6.3.9600.0",
"lessThan": "6.3.9600.23398",
"versionType": "custom",
"status": "affected"
}
]
} Windows Server 2016 Vendor product
Original vendor version evidence · not evaluated as a NuGet range {
"vendor": "Microsoft",
"product": "Windows Server 2016",
"platforms": [
"x64-based Systems"
],
"versions": [
{
"version": "10.0.14393.0",
"lessThan": "10.0.14393.9512",
"versionType": "custom",
"status": "affected"
}
]
} Windows Server 2016 (Server Core installation) Vendor product
Original vendor version evidence · not evaluated as a NuGet range {
"vendor": "Microsoft",
"product": "Windows Server 2016 (Server Core installation)",
"platforms": [
"x64-based Systems"
],
"versions": [
{
"version": "10.0.14393.0",
"lessThan": "10.0.14393.9512",
"versionType": "custom",
"status": "affected"
}
]
} Windows Server 2019 Vendor product
Original vendor version evidence · not evaluated as a NuGet range {
"vendor": "Microsoft",
"product": "Windows Server 2019",
"platforms": [
"x64-based Systems"
],
"versions": [
{
"version": "10.0.17763.0",
"lessThan": "10.0.17763.9245",
"versionType": "custom",
"status": "affected"
}
]
} Windows Server 2019 (Server Core installation) Vendor product
Original vendor version evidence · not evaluated as a NuGet range {
"vendor": "Microsoft",
"product": "Windows Server 2019 (Server Core installation)",
"platforms": [
"x64-based Systems"
],
"versions": [
{
"version": "10.0.17763.0",
"lessThan": "10.0.17763.9245",
"versionType": "custom",
"status": "affected"
}
]
} Windows Server 2022 Vendor product
Original vendor version evidence · not evaluated as a NuGet range {
"vendor": "Microsoft",
"product": "Windows Server 2022",
"platforms": [
"x64-based Systems"
],
"versions": [
{
"version": "10.0.20348.0",
"lessThan": "10.0.20348.5622",
"versionType": "custom",
"status": "affected"
}
]
} Windows Server 2025 Vendor product
Original vendor version evidence · not evaluated as a NuGet range {
"vendor": "Microsoft",
"product": "Windows Server 2025",
"platforms": [
"x64-based Systems"
],
"versions": [
{
"version": "10.0.26100.0",
"lessThan": "10.0.26100.33438",
"versionType": "custom",
"status": "affected"
}
]
} Windows Server 2025 (Server Core installation) Vendor product
Original vendor version evidence · not evaluated as a NuGet range {
"vendor": "Microsoft",
"product": "Windows Server 2025 (Server Core installation)",
"platforms": [
"x64-based Systems"
],
"versions": [
{
"version": "10.0.26100.0",
"lessThan": "10.0.26100.33438",
"versionType": "custom",
"status": "affected"
}
]
} Original source record · Cite this exact observation · Complete original publisher JSON