high Known exploitedREV. 01

CVE-2026-42897Microsoft Exchange — script injection in Outlook Web Access

Microsoft Exchange Server does not neutralise input when it builds a web page, so an attacker can get JavaScript running inside another user's Outlook Web Access session and control what that user is shown.

YOUR NEXT MOVE

Apply the Exchange security update now; until it is on, review Outlook Web Access for unexpected content and treat new mailbox rules as suspicious.

Read the risk

THE VITAL STATS
CVSS score
6.1/ 10
CVSS v3.1
EPSS probability
72%
Likelihood of exploitation
Attack complexity
Low
Conditions needed to exploit
Known exploited
Yes — CISA KEV
CVE published
2026-05-14
Added to KEV
2026-05-15
Exploit published
Not recorded
Confidence
high
Kill chain
execution
MITRE ATT&CK
T1059.007
Severity
high

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Attacker needsThe victim must open attacker-supplied content in Outlook Web Access.

Behind the card

3 REFERENCES
Field-level provenanceTRACE THE SOURCES +

Which source supports each field, when it was retrieved, and who extracted it.

FieldsSourceRetrievedExtractorConfidence
cvss, exploitation.attack_complexity, exploitation.exploit_available, references, published_atnvd.nist.gov2026-09-24scrty-crds-pipeline/0.1high
exploitation.known_exploited, exploitation.kev_addedcisa.gov2026-09-24scrty-crds-pipeline/0.1high
epssapi.first.org2026-09-24scrty-crds-pipeline/0.1high
title, summary, severity, remediation, mitre_attack, kill_chain, recommended_action, confidence, tags, exploitation.prerequisitesnvd.nist.gov2026-09-24claude-codehigh

Printing history

THE RECORD
  1. r1Initial base card

First printing. This card has not been reprinted since publication.

crds:cve-2026-42897 · CRDS 0.1 · Issued 2026-09-24