Exploitation evidence
Known exploited · CISA KEV listed
Added 2026-05-15. Ransomware campaign use: Unknown.
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.
CISA due date: 2026-05-29. This is the catalog’s deadline, not an assessment of your organization’s exposure.
KEV checked 13 Nov 2026, 00:20 Jerusalem · Original catalog ↗Reported products and versions
Microsoft / Microsoft Exchange Server 2016 Cumulative Update 23
Default status: Not specified
- affected: 15.01.0.0 to < 15.01.2507.069 (custom)
Microsoft / Microsoft Exchange Server 2019 Cumulative Update 14
Default status: Not specified
- affected: 15.02.0.0 to < 15.02.1544.041 (custom)
Microsoft / Microsoft Exchange Server 2019 Cumulative Update 15
Default status: Not specified
- affected: 15.02.0.0 to < 15.02.1748.046 (custom)
Microsoft / Microsoft Exchange Server Subscription Edition RTM
Default status: Not specified
- affected: 15.02.0.0 to < 15.02.2562.043 (custom)
Fixes and workarounds
No explicit solution text in the downloaded CVE record. Consult the vendor advisory; unaffected version ranges are shown above as reported, not inferred as a patch recommendation.
Sources and related reporting
Observed change timeline
History begins when Egret first downloads each source. It is not the complete upstream CVE history.
12 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-12",
"epss": 0.70662,
"percentile": 0.99403
}10 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-10",
"epss": 0.70662,
"percentile": 0.99399
}09 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-09",
"epss": 0.70662,
"percentile": 0.99398
}08 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-08",
"epss": 0.70662,
"percentile": 0.99398
}07 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-07",
"epss": 0.70662,
"percentile": 0.99398
}06 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-06",
"epss": 0.70662,
"percentile": 0.99397
}06 Nov 2026, 06:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-05",
"epss": 0.70662,
"percentile": 0.99396
}04 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-04",
"epss": 0.70662,
"percentile": 0.99395
}03 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-03",
"epss": 0.70662,
"percentile": 0.99395
}03 Nov 2026, 12:20 Jerusalem · CVE Program record changed
Stored CNA snapshot at this observation.
{
"containers": {
"adp": [
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2026-42897",
"options": [
{
"Exploitation": "active"
},
{
"Automatable": "no"
},
{
"Technical Impact": "total"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-05-14T00:00:00+00:00",
"version": "2.0.3"
},
"type": "ssvc"
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},
{
"other": {
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"cna": {
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{
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],
"product": "Microsoft Exchange Server 2016 Cumulative Update 23",
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"cpeApplicability": [
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{
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"value": "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."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 8.1,
"baseSeverity": "HIGH",
"vectorString": "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",
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"tags": [
"vendor-advisory",
"patch"
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"url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-42897"
}
],
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},
"cveMetadata": {
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"datePublished": "2026-05-14T17:00:36.515Z",
"dateReserved": "2026-04-30T22:35:54.967Z",
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}03 Nov 2026, 02:22 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-02",
"epss": 0.70662,
"percentile": 0.99393
}03 Nov 2026, 02:22 Jerusalem · CISA KEV status changed
Stored KEV snapshot at this observation.
{
"cveID": "CVE-2026-42897",
"cwes": [
"CWE-79"
],
"dateAdded": "2026-05-15",
"dueDate": "2026-05-29",
"forensicTriage": "No",
"knownRansomwareCampaignUse": "Unknown",
"notes": "https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2026-42897 ; https://learn.microsoft.com/en-us/exchange/plan-and-deploy/post-installation-tasks/security-best-practices/exchange-emergency-mitigation-service ; https://nvd.nist.gov/vuln/detail/CVE-2026-42897",
"product": "Microsoft",
"requiredAction": "Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.",
"shortDescription": "Microsoft Exchange Server contains a cross-site scripting vulnerability during web page generation in Outlook Web Access and when certain interaction conditions are met, arbitrary JavaScript can be executed in the browser context.",
"vendorProject": "Microsoft",
"vulnerabilityName": "Microsoft Exchange Server Cross-Site Scripting Vulnerability"
}