CVE-2026-108427: microsoft 365_apps Improper Input Validation
CVSS: 8.8v3.1HighAnalyzed
Published 15-10-2026Last modified 19-10-2026
Vulnerability summary
CVE-2026-108427 is a high (CVSS 8.8) Improper Input Validation vulnerability in microsoft 365_apps. EPSS estimates a 0.46% chance of exploitation in the next 30 days, higher than 38.8% of scored vulnerabilities.
CVSS score
8.8/10
010
High · v3.1 (CVE.org)EPSS score
0.46%
0%100%
Low · Change unavailableKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded
Timeline
- 15-10-2026PublishedVulnerability first disclosed.
- 19-10-2026Last modifiedVulnerability information updated.
Description
Heap-based buffer overflow in Microsoft Office Word allows an unauthorized attacker to execute code over a network.
CVSS metrics
2 scores · 2 sources · 1 versionHigh 8.8Preferred score · CVE.org (CNA)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:CSourcesAll 2 agree
- NVDNIST8.8HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS trend
Probability
0.46%
Chance of exploitation in the next 30 days
Percentile
39%
Versus all other CVEs
30-day change
Change unavailable
Change unavailable
16-10-202620-10-2026
EPSS score0.46%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root cause- CWE-20Improper Input ValidationThe product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
- 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().
Affected systems
Microsoft6 products
- 365_appsna
- microsoft 365 apps for enterprise≥ 16.0.1, < https://aka.ms/OfficeSecurityReleases
- microsoft office ltsc 2021≥ 16.0.1, < 16.0.14334.20974
- microsoft office ltsc 2024≥ 16.0.0, < 16.0.17932.21056
- office_2021na
1 vendor · 6 products
