CVE-2025-30388: microsoft 365_copilot Heap-based Buffer Overflow
CVSS: 7.8v3.1HighAnalyzed
Published 13-05-2025Last modified 26-02-2026
Vulnerability summary
CVE-2025-30388 is a high (CVSS 7.8) Heap-based Buffer Overflow vulnerability in microsoft 365_copilot. EPSS estimates a 4.38% chance of exploitation in the next 30 days, higher than 91.1% of scored vulnerabilities.
CVSS score
7.8/10
010
High · v3.1 (CVE.org)EPSS score
4.38%
0%100%
Low · +0.46 pp in 30 daysKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded
Timeline
- 13-05-2025PublishedVulnerability first disclosed.
- 26-02-2026Last modifiedVulnerability information updated.
Description
Heap-based buffer overflow in Windows Win32K - GRFX allows an unauthorized attacker to execute code locally.
CVSS metrics
2 scores · 2 sources · 1 versionHigh 7.8Preferred score · CVE.org (CNA)
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:CSourcesAll 2 agree
- NVDNIST7.8HighCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS trend
Probability
4.38%
Chance of exploitation in the next 30 days
Percentile
91%
Versus all other CVEs
30-day change
+0.46 pp
From 3.91% on 19-09-2026
19-09-202619-10-2026
EPSS score4.38%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root cause- CWE-122Heap-based Buffer OverflowA heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().
- CWE-787Out-of-bounds WriteThe product writes data past the end, or before the beginning, of the intended buffer.
Affected systems
Microsoft42 products
- 365_copilot< 16.0.18827.20000
- microsoft office for android≥ 16.0.1, < 16.0.18827.20000
- microsoft office for universal≥ 16.0.1, < 16.0.14326.22502
- microsoft office ltsc for mac 2021≥ 16.0.1, < 16.97.25042725
- microsoft office ltsc for mac 2024≥ 16.0.0, < 16.97.25042725
1 vendor · 42 products
