How severe is CVE-2025-53766?

CVE-2025-53766 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2025-53766 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 7% (93rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-53766?

CVE-2025-53766 primarily affects Microsoft 365 Copilot. In total, 23 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2025-53766?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

Does CVE-2025-53766 have an EU (EUVD) identifier?

Yes. CVE-2025-53766 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-24289.

When was CVE-2025-53766 published?

CVE-2025-53766 was published on 2025-08-12 and last updated on 2026-06-17.

CVE-2025-53766

CVE-2025-53766 is a critical-severity vulnerability in Microsoft 365 Copilot with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-122.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
EPSS exploit prediction: 7% (93rd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-24289
Weakness: CWE-122
Affected product: Microsoft 365 Copilot
Published: 2025-08-12
Last modified: 2026-06-17

Description

Heap-based buffer overflow in Windows GDI+ allows an unauthorized attacker to execute code over a network.

Frequently asked questions

What is CVE-2025-53766?: Heap-based buffer overflow in Windows GDI+ allows an unauthorized attacker to execute code over a network.
How severe is CVE-2025-53766?: CVE-2025-53766 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2025-53766 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 7% (93rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-53766?: CVE-2025-53766 primarily affects Microsoft 365 Copilot. In total, 23 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2025-53766?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2025-53766 have an EU (EUVD) identifier?: Yes. CVE-2025-53766 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-24289.
When was CVE-2025-53766 published?: CVE-2025-53766 was published on 2025-08-12 and last updated on 2026-06-17.

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-53766

Affected products (23)

cpe:2.3:a:microsoft:365_copilot:*:*:*:*:*:android:*:*
cpe:2.3:a:microsoft:office:*:*:*:*:*:universal:*:*
cpe:2.3:o:microsoft:windows_10_1507:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_10_1507:*:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_11_22h2:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_11_23h2:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_11_24h2:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2008:-:sp2:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_server_2008:-:sp2:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_server_2008:r2:sp1:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_server_2012:-:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2012:r2:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2016:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2022:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2022_23h2:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2025:*:*:*:*:*:*:*:*

More vulnerabilities in Microsoft 365 Copilot

CVE-2026-54130 — Critical (CVSS 9.8): Missing authentication for critical function in M365 Copilot allows an unauthorized attacker to disclose information…
CVE-2025-60724 — Critical (CVSS 9.8): Heap-based buffer overflow in Microsoft Graphics Component allows an unauthorized attacker to execute code over a…
CVE-2021-43905 — Critical (CVSS 9.6): Microsoft Office app Remote Code Execution Vulnerability
CVE-2026-41106 — Critical (CVSS 9.3): Url redirection to untrusted site ('open redirect') in M365 Copilot allows an unauthorized attacker to elevate…
CVE-2026-41090 — Critical (CVSS 9.3): Improper neutralization of special elements used in a command ('command injection') in Microsoft Copilot allows an…
CVE-2026-33102 — Critical (CVSS 9.3): Url redirection to untrusted site ('open redirect') in M365 Copilot allows an unauthorized attacker to elevate…

All CVEs affecting Microsoft 365 Copilot →

Other CWE-122 (Heap-based Buffer Overflow) vulnerabilities

CVE-2026-46752 — Critical (CVSS 10.0): Redis Lua HEAP overflow in cjson library vulnerability in Apache Kvrocks. This issue affects Apache Kvrocks: from…
CVE-2026-24822 — Critical (CVSS 10.0): Out-of-bounds Write, Heap-based Buffer Overflow vulnerability in ttttupup wxhelper (src modules). This vulnerability is…
CVE-2025-23123 — Critical (CVSS 10.0): A malicious actor with access to the management network could execute a remote code execution (RCE) by exploiting a…
CVE-2022-34819 — Critical (CVSS 10.0): A vulnerability has been identified in SIMATIC CP 1242-7 V2 (All versions < V3.3.46), SIMATIC CP 1243-1 (All versions <…
CVE-2026-44050 — Critical (CVSS 9.9): A heap-based buffer overflow in the CNID daemon comm_rcv() function in Netatalk 2.0.0 through 4.4.2 allows a remote…
CVE-2026-49841 — Critical (CVSS 9.8): FreeSWITCH is a Software Defined Telecom Stack enabling the digital transformation from proprietary telecom switches to…

Browse all CWE-122 (Heap-based Buffer Overflow) vulnerabilities →