Latest cybersecurity reporting from selected sources.

Microsoft has disclosed that a privilege escalation and a denial-of-service flaw in Defender has come under active exploitation in the wild

Coordinated action by FBI, Europol and others seizes infrastructure, makes arrests – and sends warning letters to known DDoS service users

F5 has reclassified a BIG-IP APM denial-of-service (DoS) vulnerability as a critical-severity remote code execution (RCE) flaw, warning that attackers are exploiting it to deploy webshells on unpatched devices. [...]

Researcher: If Exploited, Bug Could Crash Hospital Medical Imaging SystemsThe Cybersecurity Infrastructure and Security Agency is warning of a high severity in Grassroots DICOM, an open-source library commonly used for medical imaging products, that if exploited could allow an attacker to send a specially crafted file resulting in a denial-of-service situation.

DDoS attack frequency has risen to ‘alarming levels,’ warns Radware report

GitLab has patched a high-severity two-factor authentication bypass impacting community and enterprise editions of its software development platform. [...]

The U.K. government is warning of continued malicious activity from Russian-aligned hacktivist groups targeting critical infrastructure and local government organizations in the country in disruptive denial-of-service (DDoS) attacks. [...]

Palo Alto Networks patched a high-severity vulnerability that could allow unauthenticated attackers to disable firewall protections in denial-of-service (DoS) attacks. [...]

French postal service warns of “major network incident” just before Christmas

2 More Vulnerabilities Need Patching in React Server Components, Warns VercelMass exploitation of the "React2Shell" - CVE-2025-55182 - vulnerability remains underway by nation-state hackers tied to China, North Korea and Iran, as well as financially motivated cybercriminals running everything from cryptomining malware to DDoS services, security experts warn.

PLUS: New kind of DDOS from the Americas; Predator still hunting spyware targets; NIST issues IoT advice; And more! Infosec in Brief The Apache Foundation last week warned of a 10.0-rated flaw in its Tika toolkit.…

Cisco on Wednesday disclosed that it became aware of a new attack variant that's designed to target devices running Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software releases that are susceptible to CVE-2025-20333 and CVE-2025-20362

Cisco has warned of a high-severity security flaw in IOS Software and IOS XE Software that could allow a remote attacker to execute arbitrary code or trigger a denial-of-service (DoS) condition under specific circumstances

Citrix warns that patching recently disclosed vulnerabilities that can be exploited to bypass authentication and launch denial-of-service attacks may also break login pages on NetScaler ADC and Gateway appliances. [...]

Citrix is warning that a vulnerability in NetScaler appliances tracked as CVE-2025-6543 is being actively exploited in the wild, causing devices to enter a denial of service condition. [...]

Geopolitical Conflict Involving Iran, Israel, US Ripe for Attacks on SectorGovernment authorities are warning of increased risk of Iranian cyber and related threats against healthcare and public health sector organizations - including ransomware, distributed denial-of-service and other attacks related to that nation's escalated conflicts with Israel and the U.S.

Analysts Warn US Infrastructure May Be Next as Iran Plans Missile Strike ResponseIsrael’s strike on Iranian military and nuclear targets has triggered fears of retaliatory cyberattacks, with analysts warning that Tehran may escalate disruptions against U.S. and Israeli critical infrastructure through proxy campaigns, brute-force attacks or coordinated DDoS strikes.

Cybersecurity researchers are warning of continued risks posed by a distributed denial-of-service (DDoS) malware known as XorDDoS, with 71.3 percent of the attacks between November 2023 and February 2025 targeting the United States

Cisco has released security updates to patch a ClamAV denial-of-service (DoS) vulnerability, which has proof-of-concept (PoC) exploit code. [...]

Cloudflare warns of a surge in hyper-volumetric DDoS after revealing it stopped a massive 5.6Tbps attack