CVE-2026-55058Patch(microsoft / 365_apps)

LOWCVSS 7.8 · HIGH

Signal is active with 1 mentions in latest observed window

Immediate actions

  • Patch microsoft 365_apps systems immediately

Recommended action window: Monitor and triage in normal cycle

NVD description

Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to execute code locally.

1.0/ 10 priority

Sources & remediation

Weakness type (CWE)
CWE-125

Priority

LOW

Exploitation

NONE

PoC

NONE

Patch

AVAILABLE

Momentum

NONE

Are you affected?

If you run products in this scope, you should treat this CVE as relevant to your environment.

  • 365_apps
  • excel
  • microsoft_365
  • office_2019

Threat summary

  • Patch or workaround signal is available
  • 1 mentions across 1 observed day

What's happening

  • Patch or workaround mentioned in 1 signal
  • Technical details provided in 1 signal
  • 1 total mentions across 1 day

Affected systems

Vendors
Products
365_appsexcelmicrosoft_365office_2019office_2021office_2024office_online_server

2 versions affected across 7 products

Deep dive

Activity timeline1 mentions / 1d
00111Mentions · 2026-07-15: 1Patch / Workaround · 2026-07-15: 1Technical Details · 2026-07-15: 107-15
Signal classification1 categories
Patch
1100.0%
Referenced assets1 URL
Full discourse1 post
  • Windows Forum@windowsforum
    Patch

    🪟 AV:L doesn’t mean “harmless”—it means the attacker needs you to open the booby-trapped Excel file first. July’s Office updates fix the RCE; your inbox remains the delivery system. https://windowsforum.com/threads/cve-2026-55058-patch-excel-rce-in-july-14-office-updates.438725/?utm_source=x&utm_medium=social&utm_campaign=news_node84 #RemoteCodeExecution #MicrosoftExcel #OfficeSecurityUpdates #Cve202655058 https://t.co/XbIgjXkpPq

    Post summary

    The post announces that Microsoft Office’s July updates contain a patch for CVE‑2026‑55058, a remote code execution flaw in Excel, without referencing any PoC, exploit code, or active exploitation reports.

    0000010
    1.2K followersView on X
CPE platform detail14 entries

14 of 14 entries

PartVendorProductVersionTarget SWTarget HW
Appmicrosoft365_apps--x64
Appmicrosoft365_apps--x86
Appmicrosoftexcel2016-x64
Appmicrosoftexcel2016-x86
Appmicrosoftmicrosoft_365-macos-
Appmicrosoftoffice_2019--x64
Appmicrosoftoffice_2019--x86
Appmicrosoftoffice_2021--x64
Appmicrosoftoffice_2021--x86
Appmicrosoftoffice_2021-macos-
Appmicrosoftoffice_2024--x64
Appmicrosoftoffice_2024--x86
Appmicrosoftoffice_2024-macos-
Appmicrosoftoffice_online_server---

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