CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
Called exploited the same day it was disclosed.
Measured from the CVE publication date to the earliest of 3 KEV catalogues that list it.
The life of this vulnerability
- CVE published
- First KEV listingsame day
- Last KEV listing1d
- Last sighting3mo
Gaps are compressed to equal steps. The elapsed time is printed under each.
Which catalogues call it exploited
- CISA KEVUS federallisted May 15, 2026
- EUVDENISA, European Unionlisted May 15, 2026
- VulnCheck KEVcommercial researchlisted May 14, 2026
- CIRCLaggregator, mirrors the abovelisted May 15, 2026, not counted
3 catalogues list it. CIRCL aggregates the others and is shown but not counted.
Public exploitation evidence
- reported exploitationwww.recordedfuture.com/blog/july-2026-cve-landscape
- reported exploitationwww.proofpoint.com/us/blog/threat-insight/cleaning-out-inbox
- reported exploitationasec.ahnlab.com/en/94360/
- reported exploitationwww.proofpoint.com/us/blog/threat-insight/more-cves-same-pla
- reported exploitationwww.cisa.gov/sites/default/files/feeds/known_exploited_vulne
- reported exploitationapi.msrc.microsoft.com/cvrf/v3.0/cvrf/2026-May
8 public reports collected from VulnCheck and CIRCL, first on May 14, 2026. Each links to its original source. We have not verified them.
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.
Required action (CISA)
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
