The Microsoft Office Online Server or Office Web Apps installation on the remote host is missing security updates. It is, therefore, affected by multiple vulnerabilities:

  - Use after free in Microsoft Office Excel allows an unauthorized attacker to execute code locally.
    (CVE-2026-47642, CVE-2026-54131, CVE-2026-55948)

  - Untrusted pointer dereference in Microsoft Office Excel allows an unauthorized attacker to disclose     information locally. (CVE-2026-48580, CVE-2026-55138)

  - Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to disclose information     locally. (CVE-2026-50408, CVE-2026-54988, CVE-2026-55046, CVE-2026-55122, CVE-2026-55898)

  - Heap-based buffer overflow in Microsoft Office Excel allows an unauthorized attacker to execute code     locally. (CVE-2026-50675, CVE-2026-55029, CVE-2026-55037, CVE-2026-55041, CVE-2026-55053, CVE-2026-55131,     CVE-2026-55947, CVE-2026-58618)

  - Heap-based buffer overflow in Microsoft Office Excel allows an unauthorized attacker to disclose     information locally. (CVE-2026-50678)

  - Access of resource using incompatible type ('type confusion') in Microsoft Office Excel allows an     unauthorized attacker to execute code locally. (CVE-2026-55024, CVE-2026-55025)

  - Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to execute code locally.
    (CVE-2026-55031, CVE-2026-55044, CVE-2026-55058)

  - Buffer over-read in Microsoft Office Excel allows an unauthorized attacker to execute code locally.
    (CVE-2026-55036)

  - Integer underflow (wrap or wraparound) in Microsoft Office Excel allows an unauthorized attacker to     execute code locally. (CVE-2026-55039)

  - Integer overflow or wraparound in Microsoft Office Excel allows an unauthorized attacker to execute code     locally. (CVE-2026-55048)

  - Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to disclose information over     a network. (CVE-2026-55054)

  - Untrusted pointer dereference in Microsoft Office Excel allows an unauthorized attacker to execute code     locally. (CVE-2026-55136)

  - Stack-based buffer overflow in Microsoft Office Excel allows an unauthorized attacker to execute code     locally. (CVE-2026-55141, CVE-2026-55899)

  - Use of uninitialized resource in Microsoft Office Excel allows an unauthorized attacker to execute code     locally. (CVE-2026-55949)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Detections

Analytics

Security Updates for Microsoft Office Online Server (July 2026)

high Nessus Plugin ID 326872

Version 1.4

Version 1.2

Version 1.1

Version 1.4 Jul 18, 2026, 3:00 PM CVSS metrics ("CVSSv3 vector" set to "CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H") CVSSv3 score source (changed from "CVE-2026-58618" to "CVE-2026-55898") Plugin metadata (Add IAVM Info) Plugin Feed: 202607181500
Version 1.2 Jul 15, 2026, 7:54 AM CVSS metrics ("CVSSv2 score" set to 7.2) CVSS metrics ("CVSSv2 vector" set to "CVSS2#AV:L/AC:L/Au:N/C:C/I:C/A:C") CVSS temporal metrics ("CVSSv2 temporal vector" set to "CVSS2#E:U/RL:OF/RC:C") CVSS temporal metrics ("CVSSv3 temporal vector" set to "CVSS:3.0/E:U/RL:O/RC:C") CVSSv2 score source (changed from "CVE-2026-47642" to "CVE-2026-55949") CVSSv3 score source (set to "CVE-2026-58618") Exploit attributes ("Exploit available" set to "False") Exploit attributes ("Exploitability ease" set to "No known exploits are available") Plugin Feed: 202607150754
Version 1.1 Jul 15, 2026, 2:58 AM New Plugin Feed: 202607150258