VulnSocial

CVE-2026-55039Patch(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

Integer underflow (wrap or wraparound) in Microsoft Office Excel allows an unauthorized attacker to execute code locally.

microsoft CVEsBack to dashboard
1.0/ 10 priority

Sources & remediation

Patch / fix
Weakness type (CWE)
CWE-122CWE-191

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
microsoft
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

    🪟 Excel files are having another “just open me” moment: CVE-2026-55039 can run code once a booby-trapped workbook lands on your PC. July 14 updates beat malware’s favorite invitation. https://windowsforum.com/threads/cve-2026-55039-fix-excel-code-execution-with-july-14-updates.438693/?utm_source=x&utm_medium=social&utm_campaign=news_node84 #RemoteCodeExecution #OfficeSecurity #MicrosoftExcel #Cve202655039 https://t.co/bjBqIQBmtx

    Post summary

    The post indicates CVE‑2026‑55039 is a remote code execution flaw in Excel that can be prevented by applying the July 14 updates.

    0000037
    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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