CVE-2026-55898: microsoft 365_apps Out-of-bounds Read
CVSS: 7.1v3.1HighAnalyzed
Published 14-07-2026Last modified 08-10-2026
Vulnerability summary
CVE-2026-55898 is a high (CVSS 7.1) Out-of-bounds Read vulnerability in microsoft 365_apps. EPSS estimates a 0.47% chance of exploitation in the next 30 days, higher than 39.8% of scored vulnerabilities.
CVSS score
7.1/10
010
High · v3.1 (NVD)EPSS score
0.47%
0%100%
Low · 0.00 pp in 30 daysKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded
Timeline
- 14-07-2026PublishedVulnerability first disclosed.
- 08-10-2026Last modifiedVulnerability information updated.
Description
Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to disclose information locally.
CVSS metrics
2 scores · 2 sources · 1 versionHigh 7.1Preferred score · NVD (NIST)
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:HSources2 sources · 6.1–7.1
- CVE.orgCNA6.1MediumCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H/E:U/RL:O/RC:CDiffers
EPSS trend
Probability
0.47%
Chance of exploitation in the next 30 days
Percentile
40%
Versus all other CVEs
30-day change
0.00 pp
From 0.47% on 21-09-2026
21-09-202621-10-2026
EPSS score0.47%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Microsoft15 products
- 365_appsna
- excel2016
- microsoft_365na
- microsoft 365 apps for enterprise≥ 16.0.1, < https://aka.ms/OfficeSecurityReleases
- microsoft excel 2016≥ 16.0.0.0, < 16.0.5561.1001
1 vendor · 15 products
