8.1

CVE-2026-42897: Microsoft Exchange Server Cross-Site Scripting Vulnerability

CVSS: 8.1v3.1HighKEVAnalyzed
Published 14-05-2026Last modified 10-08-2026
Open JSON

Vulnerability summary

CVE-2026-42897 is a high (CVSS 8.1) Cross-site Scripting vulnerability in Microsoft. It is known to be exploited: CISA and ENISA list it, first on 15-05-2026. EPSS estimates a 0.52% chance of exploitation in the next 30 days, higher than 43.2% of scored vulnerabilities.

Overall risk
85/100
0100
Critical · default modelHow is this calculated?
CVSS score
8.1/10
010
High · v3.1 (CVE.org)
EPSS score
0.52%
0%100%
Low · -71.25 pp in 30 days
KEVListedCISA · ENISA
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 14-05-2026
    PublishedVulnerability first disclosed.
  2. 15-05-2026
    Added to CISA KEVMicrosoft Exchange Server Cross-Site Scripting Vulnerability
  3. 29-05-2026
    CISA remediation dueApply mitigations per vendor instructions.
  4. 10-08-2026
    Last modifiedVulnerability information updated.
  5. 18-08-2026
    Added to ENISA KEVAdded to the ENISA known exploited vulnerabilities catalog.

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.

CVSS metrics

2 scores · 2 sources · 1 version

EPSS trend

Probability

0.52%

Chance of exploitation in the next 30 days

Percentile

43%

Versus all other CVEs

30-day change

-71.25 pp

From 71.77% on 21-09-2026

21-09-202621-10-2026
EPSS score
0.52%

Known exploited

Compare KEV catalogs
CISA KEVListed
Added
15-05-2026
Federal due date
29-05-2026
ENISA CNWListed
Added
18-08-2026

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. msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2026-42897 learn.microsoft.com/en-us/… nvd.nist.gov/vuln/detail/CVE-2026-42897

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Microsoft6 products
  • exchange_serverEOL2016 | 2016:cumulative_update_1 | 2016:cumulative_update_10 | 2016:cumulative_update_11 | 2016:cumulative_update_12 | 2016:cumulative_update_13 | 2016:cumulative_update_14 | 2016:cumulative_update_15 | 2016:cumulative_update_16 | 2016:cumulative_update_17 | 2016:cumulative_update_18 | 2016:cumulative_update_19 | 2016:cumulative_update_2 | 2016:cumulative_update_20 | 2016:cumulative_update_21 | 2016:cumulative_update_22 | 2016:cumulative_update_23 | 2016:cumulative_update_3 | 2016:cumulative_update_4 | 2016:cumulative_update_5 | 2016:cumulative_update_6 | 2016:cumulative_update_7 | 2016:cumulative_update_8 | 2016:cumulative_update_9 | 2019 | 2019:cumulative_update_1 | 2019:cumulative_update_10 | 2019:cumulative_update_11 | 2019:cumulative_update_12 | 2019:cumulative_update_13 | 2019:cumulative_update_14 | 2019:cumulative_update_2 | 2019:cumulative_update_3 | 2019:cumulative_update_4 | 2019:cumulative_update_5 | 2019:cumulative_update_6 | 2019:cumulative_update_7 | 2019:cumulative_update_8 | 2019:cumulative_update_9
  • exchange_server_subscription_edition< 15.02.2562.043
  • microsoft exchange server 2016 cumulative update 23≥ 15.01.0.0, < 15.01.2507.069
  • microsoft exchange server 2019 cumulative update 14≥ 15.02.0.0, < 15.02.1544.041
  • microsoft exchange server 2019 cumulative update 15≥ 15.02.0.0, < 15.02.1748.046

1 vendor · 6 products

References

2 links