CVE-2026-42897 kev in the critical feed json
Microsoft Exchange Server Spoofing Vulnerability
published 2026-05-14 5 mo ago modified 2026-10-26 13 d ago also EUVD-2026-30343
- cvss
- 8.1
- version 3.1, CNA
- cisa kev
- Exploited
- added 2026-05-15
- epss
- 70.7%
- EPSS 70.7% chance of exploitation in 30 days, percentile 99.3%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
cisa required action Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
- Microsoft Microsoft Exchange Server 2016 Cumulative Update 23 15.01.2507.069
- Microsoft Microsoft Exchange Server 2019 Cumulative Update 14 15.02.1544.041
- Microsoft Microsoft Exchange Server 2019 Cumulative Update 15 15.02.1748.046
- Microsoft Microsoft Exchange Server Subscription Edition RTM 15.02.2562.043
Timeline
- 0-day patched (Project Zero)
- CISA SSVC: exploitation active
- Published
- Added to CISA KEV
- CISA patch deadline
Known exploited
- Added
- 5 mo ago
- Patch by
- 2026-05-29 (5 mo ago)
- Ransomware
- Not known
- Required action
- Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
- Vendor, product
- Microsoft, Microsoft
- CISA name
- Microsoft Exchange Server Cross-Site Scripting Vulnerability
Zero-day
Detected in real attacks while still unknown to the vendor and the public, per Google Project Zero's 0day In-the-Wild tracker.
- Patched
- 2026-05-14
- Details
- project zero tracker
CISA SSVC
- Exploitation
- Active, exploited in the wild
- Automatable
- no
- Technical impact
- total
- Assessed
- 5 mo ago
Exploit prediction
70.66% chance of exploitation in the next 30 days, higher than 99.3% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 8.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N/E:F/RL:O/RC:C |
| CNA | 3.1 | 8.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N |
| NVD | 3.1 | 6.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N |
Affected products
- Microsoft Microsoft Exchange Server 2016 Cumulative Update 23
- Microsoft Microsoft Exchange Server 2019 Cumulative Update 14
- Microsoft Microsoft Exchange Server 2019 Cumulative Update 15
- Microsoft Microsoft Exchange Server Subscription Edition RTM
Classification
- Weakness
-
- CWE-79 Improper Neutralization of Input During Web Page Generation
- Technology feeds
References
-
msrc.microsoft.com
/update-guide/vulnerability/CVE-2026-42897
vendor-advisory, patch, mitigation
-
cisa.gov
/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-42897
government-resource, us-government-resource
Sources
- CVE List CVE-2026-42897
- NVD CVE-2026-42897
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