CVE-2026-45455 | Microsoft Excel Information Disclosure Vulnerability

Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to disclose information over a network.

Published: 2026-06-09 Last update: 2026-06-19 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-45455 is rated Low Risk (26.8/100): CVSS Low severity, with low exploitation likelihood (EPSS 0.49%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-45455

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-18 0.30% 0.49% +0.20%
2 2026-06-15 0.05% 0.30% +0.24%
3 2026-06-10 — 0.05% —

Full EPSS history (3 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-45455

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
3.3 3.1 LOW
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 1.8 1.4 [email protected]
4.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 2.8 1.4 [email protected]

Weakness enumeration for CVE-2026-45455

GitHub Security Advisory for CVE-2026-45455

GHSA-mghm-jr32-gfh3 · Severity: low — Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to disclose...

Affected software / configurations for CVE-2026-45455

Vendor Product Version Raw CPE
microsoft 365_apps — cpe:2.3:a:microsoft:365_apps:-:*:*:*:enterprise:*:x64:*
microsoft 365_apps — cpe:2.3:a:microsoft:365_apps:-:*:*:*:enterprise:*:x86:*
microsoft excel 2016 cpe:2.3:a:microsoft:excel:2016:*:*:*:*:*:x64:*
microsoft excel 2016 cpe:2.3:a:microsoft:excel:2016:*:*:*:*:*:x86:*
microsoft microsoft_365 — cpe:2.3:a:microsoft:microsoft_365:-:*:*:*:*:macos:*:*
microsoft office_2019 — cpe:2.3:a:microsoft:office_2019:-:*:*:*:*:*:x64:*
microsoft office_2019 — cpe:2.3:a:microsoft:office_2019:-:*:*:*:*:*:x86:*
microsoft office_2021 — cpe:2.3:a:microsoft:office_2021:-:*:*:*:ltsc:-:x64:*
microsoft office_2021 — cpe:2.3:a:microsoft:office_2021:-:*:*:*:ltsc:-:x86:*
microsoft office_2021 — cpe:2.3:a:microsoft:office_2021:-:*:*:*:ltsc:macos:-:*
microsoft office_2024 — cpe:2.3:a:microsoft:office_2024:-:*:*:*:ltsc:-:x64:*
microsoft office_2024 — cpe:2.3:a:microsoft:office_2024:-:*:*:*:ltsc:-:x86:*
microsoft office_2024 — cpe:2.3:a:microsoft:office_2024:-:*:*:*:ltsc:macos:-:*
microsoft office_online_server — cpe:2.3:a:microsoft:office_online_server:-:*:*:*:*:*:*:*

References for CVE-2026-45455

cvelogic Threat Intelligence