CVE-2026-55008Microsoft Exchange Server Spoofing Vulnerability
- 9.6CriticalCVSS base score
- 0.86%Exploitation in 30 daysEPSS · top 41% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
Improper neutralization of input during web page generation ('cross-site scripting') in Microsoft Exchange Server allows an unauthorized attacker to perform spoofing over a network.
Timeline
ID reserved
By microsoft
- 28 days later
· 28 days later
Published
- 4 months later
· 4 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| microsoftCNA (assigner) | 3.1 | Critical9.6 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H/E:U/RL:O/RC:C |
| NVDNVD · Analyzed | 3.1 | Critical9.6 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 0.86% · top 41% of all CVEs (13 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: Critical 9.6.
Affected products
Microsoft · Microsoft Exchange Server 2016 Cumulative Update 23
- affected 15.01.0.0 – < 15.01.2507.071
Microsoft · Microsoft Exchange Server 2019 Cumulative Update 14
- affected 15.02.0.0 – < 15.02.1544.043
Microsoft · Microsoft Exchange Server 2019 Cumulative Update 15
- affected 15.02.0.0 – < 15.02.1748.048
Microsoft · Microsoft Exchange Server Subscription Edition RTM
- affected 15.02.0.0 – < 15.02.2562.045
References
References1
- Microsoft Exchange Server Spoofing Vulnerability (opens in a new tab)vendor-advisorypatch
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-44026 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-55008)Record last updated .