The Hacker News | #1 Trusted Source for Cybersecurity News — Index Page

Threat actors have been observed exploiting a critical pre-authentication command injection vulnerability in Citrix NetScaler ADC and NetScaler Gateway to drop web shells and attempt theft of configuration data. LevelBlue's Threat Hunt Operations & Research (THOR) team, which analyzed the exploitation activity across multiple customer environments, said it identified malicious NetScaler authentication events containing attacker-controlled usernames designed to weaponize CVE-2026-88771. CVE-2026-88771 (CVSS score: 9.5) is an improper input validation vulnerability that could allow an unauthenticated attacker to execute arbitrary commands.  The security flaw, along with CVE-2026-88772, was disclosed last week after reports that the Dutch National Cyber Security Centre (NCSC-NL) reportedly sent a pre-notification to organizations in the Netherlands that urged organizations to shut their appliances down, citing active exploitation. As of writing, there are currently no d...

Threat actors have weaponized a now-patched security flaw in Zimbra Collaboration Suite (ZCS) to deploy web shells and access mailbox data, according to findings from the Microsoft Security Research team. The attack exploits CVE-2026-73570 (CVSS score: 8.9), an unauthenticated operating system command injection flaw that can lead to remote code execution when Simple Network Management Protocol (SNMP) notifications are enabled and the optional zimbra-snmp package is installed. Exploitation of CVE-2026-73570 can be triggered by a specially crafted SMTP request (i.e., email) against exposed Zimbra servers without requiring authentication or user interaction. The vulnerability was patched by Zimbra in July 2026 with the release of version 10.1.20. "Following successful exploitation, observed activity included deployment of JSP web shells and reverse shells, privilege escalation, persistent remote-access tooling, and memory-backed execution," the tech giant said . "Th...

Microsoft has warned of phishing campaigns distributing an installer for the MSP360 Remote Monitoring and Management (RMM) software under the guise of meeting invitations, PDF-themed lures, software update prompts, and other social-engineering content. "Once executed, the legitimate MSP360 installer, distributed under a deceptive file name established remote management access on affected devices and enabled threat actors to gain an initial foothold using trusted administrative software," the Microsoft Security Research team said . The initial foothold is then used to download and install a ConnectWise ScreenConnect client, offering threat actors a redundant remote-access channel to compromised endpoints. The access is then abused to deliver additional tools and carry out information collection and credential-access operations. The activity has not been attributed to any known threat actor or group. The multi-stage intrusion chain, which the Windows maker detected in Ju...

Attackers are exploiting a new critical zero-day flaw in Cisco Catalyst SD-WAN Manager, the system companies use to manage their Cisco SD-WAN networks, Cisco said in an  advisory  on September 30. The flaw, CVE-2026-76504 , could allow a remote attacker with no login access to use the Manager's API as the admin user. Fixed releases are available, and there is no workaround. It carries a CVSS score of 9.8 out of 10. It sits in the part of the Manager's API that handles login sessions. The Manager mishandles URI encoding in an HTTP request. A crafted request can therefore bypass an authentication rule intended to restrict access to a single API endpoint. The attacker needs no credentials, only the ability to send that request to the Manager's API. Managers exposed to the internet are at risk of compromise, according to Cisco. By default, the admin user holds the netadmin role, which is allowed to perform all operations on the device. Cisco said its Product Security I...

Threat actors are abusing ChatGPT Custom GPTs to disguise them as legitimate product offerings and direct unsuspecting victims to malicious sites that employ ClickFix lures to deliver malware. Huntress, which observed the activity in late September 2026, said it marks the abuse of yet another feature in trusted artificial intelligence (AI) platforms. Prior campaigns have weaponized shared conversations with AI chatbots and malicious Claude Artifacts to distribute stealer malware and remote access trojans (RATs). Custom GPTs refer to a personalized version of ChatGPT that, as the name implies, allows users to define custom instructions, upload reference files, and enable specific skills to handle unique tasks without any coding. They are hosted on the legitimate ChatGPT website with the Custom GPT name at the top. "In the incidents we saw, victims interacted with an attacker-created Custom GPT, which was programmed to respond to their prompts with a message that includ...

Given that the browser is where business apps are accessed and used, it makes sense that attacks are happening there too. Most breaches today begin in a browser session. Often, they never leave it, with the entire attack chain from initial access to exfiltration playing out in the browser. Here are the six most dangerous techniques that should be on every security team's radar in 2026. 1. Phishing for credentials and sessions Modern phishing kits don't just steal passwords — they intercept live sessions. Reverse-proxy adversary-in-the-middle (AiTM) kits like Tycoon2FA, Sneaky2FA, and Evilginx relay credentials and session tokens in real time, bypassing most forms of MFA. These kits are sold as turnkey Phishing-as-a-Service platforms with anti-bot protection, dynamic lure generation, and automated session replay — reducing the barrier to sophisticated phishing to effectively zero. At the same time, phishing delivery has moved well beyond email — attackers deliver link...

AI coding agents asked to share screenshots of code changes for review have put internal company images in public GitHub repositories, security company Glow said. Its researchers found more than 13,000 internal images from developers at over 300 organizations, including customer billing records and screens of features not yet released. In most cases, they sat under developers' personal accounts, where anyone could download them but company security teams did not see them. The affected organizations include one of the world's largest tech companies, a leading AI lab, a major enterprise software provider, and a Fortune 500 travel company. Glow began contacting them on September 9,  published its findings  on September 29, and says others are likely affected too. In one case, a developer at a manufacturer with more than 100,000 employees asked an agent to check a fix to an internal billing screen. The agent created a public repository in the developer's personal GitHub ...