Technology · Microsoft
Microsoft Office Online Server vulnerabilities
Updated . Rebuilt every hour.
Junglewise Threat Intelligence has tracked 33 vulnerabilities in Microsoft Office Online Server: 0 in the last 7 days and 32 in the last 90 days, 0 of them critical and 0 exploited in the wild. The most recent, CVE-2026-55949, was published on 14 July 2026.
- Last 7 days
- 0
- Last 90 days
- 32
- Critical, all time
- 0
- Exploited in the wild
- 0
About Microsoft Office Online Server
A server that provides browser-based versions of Microsoft Word, PowerPoint, Excel, and OneNote.
Latest Microsoft Office Online Server vulnerabilities
- CVE-2026-55949: Microsoft Excel use of uninitialized resource code executionhighCVSS 7.8
- CVE-2026-55947: Microsoft Office Excel heap buffer overflowhighCVSS 7.8
- CVE-2026-55898: Microsoft Office Excel out-of-bounds readmediumCVSS 6.1
- CVE-2026-55141: Microsoft Office Excel stack-based buffer overflowhighCVSS 7.8
- CVE-2026-55138: Microsoft Excel untrusted pointer dereference information disclosuremediumCVSS 5.5
- CVE-2026-55137: Microsoft Office Excel heap buffer overflowhighCVSS 7.8
- CVE-2026-55136: Microsoft Excel untrusted pointer dereference remote code executionhighCVSS 7.8
- CVE-2026-55131: Microsoft Excel heap buffer overflow code executionhighCVSS 7.8
- CVE-2026-55122: Microsoft Excel out-of-bounds read information disclosurehighCVSS 7.1
- CVE-2026-55058: Microsoft Excel out-of-bounds read code executionhighCVSS 7.8
- CVE-2026-55054: Microsoft Excel out-of-bounds read information disclosuremediumCVSS 6.5
- CVE-2026-55053: Microsoft Excel heap buffer overflow code executionhighCVSS 7.8
- CVE-2026-55048: Microsoft Excel integer overflow local code executionhighCVSS 7.8
- CVE-2026-55044: Microsoft Office Excel out-of-bounds read code executionhighCVSS 7.8
- CVE-2026-55041: Microsoft Excel heap buffer overflow code executionhighCVSS 7.8
- CVE-2026-55039: Microsoft Office Excel integer underflow code executionhighCVSS 7.8
- CVE-2026-55037: Microsoft Office Excel heap buffer overflowhighCVSS 7.8
- CVE-2026-55036: Microsoft Excel buffer over-read code executionhighCVSS 7.8
- CVE-2026-55031: Microsoft Excel out-of-bounds read code executionhighCVSS 7.8
- CVE-2026-55029: Microsoft Excel heap buffer overflow in file parsinghighCVSS 7.8
- CVE-2026-55025: Microsoft Excel type confusion code executionhighCVSS 7.8
- CVE-2026-55024: Microsoft Excel type confusion code executionhighCVSS 7.8
- CVE-2026-54131: Microsoft Office Excel use after free code executionhighCVSS 7.8
- CVE-2026-50408: Microsoft Excel out-of-bounds read information disclosuremediumCVSS 5.5
- CVE-2026-48580: Microsoft Excel untrusted pointer dereference information disclosuremediumCVSS 5.5
Most severe Microsoft Office Online Server vulnerabilities
Exploited in the wild first, then by severity and CVSS score.
- CVE-2025-49697: Microsoft Office heap overflow code executionhighCVSS 8.4EPSS 0.6%
- CVE-2026-55949: Microsoft Excel use of uninitialized resource code executionhighCVSS 7.8
- CVE-2026-55947: Microsoft Office Excel heap buffer overflowhighCVSS 7.8
- CVE-2026-55141: Microsoft Office Excel stack-based buffer overflowhighCVSS 7.8
- CVE-2026-55137: Microsoft Office Excel heap buffer overflowhighCVSS 7.8
- CVE-2026-55136: Microsoft Excel untrusted pointer dereference remote code executionhighCVSS 7.8
- CVE-2026-55131: Microsoft Excel heap buffer overflow code executionhighCVSS 7.8
- CVE-2026-55058: Microsoft Excel out-of-bounds read code executionhighCVSS 7.8
- CVE-2026-55053: Microsoft Excel heap buffer overflow code executionhighCVSS 7.8
- CVE-2026-55048: Microsoft Excel integer overflow local code executionhighCVSS 7.8
Vulnerabilities per week
The last 13 weeks, by the week each vulnerability was published.
| Week of | Bar | Vulns | Critical |
|---|---|---|---|
| 29 Jun 2026 | 0 | 0 | |
| 6 Jul 2026 | 0 | 0 | |
| 13 Jul 2026 | 32 | 0 | |
| 20 Jul 2026 | 0 | 0 | |
| 27 Jul 2026 | 0 | 0 | |
| 3 Aug 2026 | 0 | 0 | |
| 10 Aug 2026 | 0 | 0 | |
| 17 Aug 2026 | 0 | 0 | |
| 24 Aug 2026 | 0 | 0 | |
| 31 Aug 2026 | 0 | 0 | |
| 7 Sep 2026 | 0 | 0 | |
| 14 Sep 2026 | 0 | 0 | |
| 21 Sep 2026 | 0 | 0 |
How this is built
Junglewise Threat Intelligence collects vulnerabilities from NVD, GitHub Security Advisories, OSV, the CISA Known Exploited Vulnerabilities catalog, FIRST EPSS and vendor advisories, and matches each one to the technologies and vendors it affects. Dates are the date a vulnerability was published, in UTC.
The pages are rebuilt from the database every hour. Frozen weekly and monthly reports never change once published, so they can be cited.
Use this data
The same data is at https://junglewise.ai/threats/technologies/office-online-server.json, for scripts and language models. It is free to reuse under CC BY 4.0 with a link back to this page.
Cite as: Junglewise Threat Intelligence, "Microsoft Office Online Server vulnerabilities", https://junglewise.ai/threats/technologies/office-online-server, 26 September 2026.