Russia-affiliated cyber espionage group Laundry Bear (aka Void Blizzard, aka TA488) is exploiting CVE-2026-42897, a cross-site scripting vulnerability in Microsoft Exchange, to target US and European government entities and a variety of private sector organizations via email. The warning comes from Proofpoint, who detected emails carrying the concealed exploit hitting inboxes. “The subject lines and lures are banal, likely so the targeted user opens and skims the message, but dismisses the message as junk without … More → The post Laundry Bear’s new Microsoft Exchange attack triggers on email open (CVE-2026-42897) appeared first on Help Net Security .

CVE-2026-42897 stems from a cross-site scripting (XSS) vulnerability and can allow an attacker to compromise Outlook Web Access (OWA) mailboxes.

The U.S. Cybersecurity and Infrastructure Security Agency (CISA) adds a flaw in Microsoft Exchange Server to its Known Exploited Vulnerabilities catalog. The U.S. Cybersecurity and Infrastructure Security Agency (CISA) added a flaw in Microsoft Exchange Server, tracked as CVE-2026-42897 (CVSS score of 8.1), to its Known Exploited Vulnerabilities (KEV) catalog. This week, Microsoft warned that threat actors are […]

Microsoft warned that attackers are exploiting a new Exchange Server zero-day vulnerability, tracked as CVE-2026-42897, in the wild. Microsoft warned that threat actors are actively exploiting a new Exchange Server zero-day vulnerability tracked as CVE-2026-42897 (CVSS score 8.1). The vulnerability is an improper neutralization of input during web page generation (‘cross-site scripting’) in Microsoft Exchange […]

CISA has added one new vulnerability to its Known Exploited Vulnerabilities (KEV) Catalog , based on evidence of active exploitation. CVE-2026-42897 Microsoft Exchange Server Cross-Site Scripting Vulnerability This type of vulnerability is a frequent attack vector for malicious cyber actors and poses significant risks to the federal enterprise. Binding Operational Directive (BOD) 22-01: Reducing the Significant Risk of Known Exploited Vulnerabilities established the KEV Catalog as a living list of known Common Vulnerabilities and Exposures (CVEs) that carry significant risk to the federal enterprise. BOD 22-01 requires Federal Civilian Executive Branch (FCEB) agencies to remediate identified vulnerabilities by the due date to protect FCEB networks against active threats. See the BOD 22-01 Fact Sheet for more information. Although BOD 22-01 only applies to FCEB agencies, CISA strongly urges all organizations to reduce their exposure to cyberattacks by prioritizing timely remediation of KEV Catalog vulnerabilities as part of their vulnerability management practice. CISA will continue to add vulnerabilities to the catalog that meet the specified criteria . 

A critical cross-site scripting (XSS) vulnerability (CVE-2026-42897) in Microsoft Exchange Server is being exploited by attackers, Microsoft warned on Thursday. A permanent fix is still in the works. In the meantime, Microsoft provided temporary mitigations. About CVE-2026-42897 CVE-2026-42897 affects on-premises versions of Microsoft Exchange Server: Subscription Edition RTM, 2019, and 2016. Exchange Online is not affected. Flagged by an anonymous researcher, the vulnerability allows an unauthorized attacker to perform spoofing over a network. “An attacker … More → The post Unpatched Microsoft Exchange Server vulnerability exploited (CVE-2026-42897) appeared first on Help Net Security .

Microsoft has disclosed a new security vulnerability impacting on-premise versions of Exchange Server that it said has come under active exploitation in the wild. The vulnerability, tracked as CVE-2026-42897 (CVSS score: 8.1), has been described as a spoofing bug stemming from a cross-site scripting flaw. An anonymous researcher has been credited with discovering and reporting the issue. "

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.