CVE-2026-54998: high-severity vulnerability in Microsoft Exchange Online
Microsoft Exchange Online Elevation of Privilege Vulnerability
Published · Updated
41Vexday Risk Score
No sign of exploitation. It has a public proof of concept.
ssvc Attendcvss 8.8epss 0.8%
from disclosure to weapon2 days
Published on NVDJul 2
1st PoC+2d
exploitation probability
0.8%top 45% of all CVEs
observed exploitation
nono source reports it
1 public exploit(s)
Incorrect authorization in Microsoft Exchange Online allows an authorized attacker to elevate privileges over a network.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
Affected products
Microsoft · Microsoft Exchange Onlinepublic PoCs found — 1
githubgithub.com/sentinel-aidefense/CVE-2026-54998-exp★ 3⚠ Public resources, to assess the exposure of systems you control or are authorized to test. Test only with authorization.
Related CVEs — Microsoft Exchange Online
In the same product, most dangerous first.
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