Loading vulnerability…
CVE-2026-42897 is an actively exploited cross-site scripting vulnerability in the Outlook Web Access component of on-premises Microsoft Exchange Server. The flaw is caused by improper neutralization of attacker-controlled input during web page generation when Exchange renders email content in OWA, allowing malicious HTML or script content embedded in a specially crafted email to execute in the victim’s browser. Exploitation occurs in the context of the victim’s authenticated OWA session after the target opens, and in some reporting previews, the crafted message in a vulnerable OWA client. Affected products include on-premises Exchange Server Subscription Edition, Exchange Server 2016, and Exchange Server 2019; Exchange Online is not affected. The vulnerability has been described by Microsoft as a spoofing issue, but the observed exploitation behavior is browser-side arbitrary JavaScript execution within OWA.
Mallory correlates every CVE against your assets, your vendors, and active adversary campaigns. Know which vulnerabilities matter for you, not just which ones are loud.
What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.
What an attacker gets, and what they’ve been doing with it.
If you can’t patch tonight, do this now.
Patch, then assume compromise.
No valid public exploits. Mallory filtered out 1 candidate as fakes, detection scripts, or README-only repos.
All candidate exploits were filtered out by Mallory's validation.
Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.
Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
351 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
A Microsoft Exchange Outlook Web Access (OWA) cross-site scripting vulnerability caused by inadequate HTML sanitization that allows malicious JavaScript to execute when a victim opens a crafted email in OWA, enabling deployment of the OWAReaper mailbox backdoor.
A Microsoft Exchange Server vulnerability listed among vulnerabilities actively exploited or operationally weaponized in July 2026.
A vulnerability exploited by TA488 to deploy the OWAReaper malware.
A maximum-severity cross-site scripting vulnerability in Microsoft Exchange Server / Outlook Web Access caused by improper filtering of HTML embedded in email, enabling malicious JavaScript execution and half-click compromise when a victim opens an email.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.