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Unknown threat actors have been observed exploiting a newly patched security flaw in Citrix NetScaler ADC and NetScaler Gateway appliances to target organizations in North America and Europe. The activity, observed by Mandiant Consulting and Google Threat Intelligence Group (GTIG) in September 2026, has targeted government, financial services, technology, education, and legal and professional services sectors. In a post shared on LinkedIn, Charles Carmakal, chief technology officer at Mandiant Consulting, said the targeted intrusions have impacted dozens of organizations, warning of "broad and opportunistic exploitation of CVE-2026-88772 and CVE-2026-88771 by a variety of threat actors in the near term." "Exploitation of CVE-2026-88772 bypasses authentication and triggers an unhandled termination of the NetScaler Packet Processing Engine (NSPPE) to establish initial root-level access," the tech giant said . The attacks have been observed weaponizing the f...

A High-severity OpenSSL flaw can leak heap memory to the other side of a DTLS connection or crash the program,  OpenSSL said  on September 29 as it released fixes. DTLS , the TLS variant used for UDP traffic, resends a handshake message if no reply arrives before the timer expires. The leak or crash can happen when such a resend starts while a larger handshake message is stuck part-way through being sent. The flaw, tracked as CVE-2026-84782, is fixed in  OpenSSL 4.0.3, 3.6.5, 3.5.9 and 3.4.8 . Fixed versions for the older 3.0, 1.1.1 and 1.0.2 branches go only to customers who pay for OpenSSL's premium support. OpenSSL 3.0  stopped getting public security fixes  on September 7. OpenSSL has not said whether an attacker can cause a resend while a message is stuck, nor has it reported any attacks exploiting the flaw. DTLS is used, for example, to protect WebRTC data channels and to set up encryption keys for internet calls. Software is exposed to this fla...

Cybersecurity researchers have disclosed technical details of a recently patched critical security flaw in Citrix NetScaler ADC and Gateway that has come under active exploitation in the wild. The vulnerability, tracked as CVE-2026-88772 (CVSS score: 9.5), has been described as a memory overflow bug in the Datagram Transport Layer Security (DTLS) protocol handling that's rooted in the NetScaler Packet Processing Engine (NSPPE). "Citrix NetScaler ADC and NetScaler Gateway contain an improper restriction of operations within the bounds of a memory buffer vulnerability that could allow for remote code execution or denial-of-service," the U.S. Cybersecurity and Infrastructure Security Agency (CISA) said . The issue, per watchTowr , is that NetScaler implicitly trusts the declared fragment size in the DTLS handshake header's fragment_length field (i.e., 1 byte), while the header simultaneously claims that the complete message, as denoted by the length field, is 120...

A group of academics from VUSec and Scuola Superiore Sant'Anna have disclosed details of a new Spectre CPU vulnerability variant that affects Just-In-Time ( JIT ) engines present in web browsers, language runtimes, and the operating system kernel, across multiple CPU vendors. The new Spectre v2 variant has been codenamed Branch Target Reuse (BTR) . "The key insight is that, while modern CPUs restore architectural code coherence after self-modification, they do not necessarily invalidate stale indirect branch prediction entries (i.e., branch targets)," researchers Sander Wiebing, Yuhui Zhu, Alessandro Biondi, and Cristiano Giuffrida said in an accompanying paper. "In JIT engines, these stale targets can outlive the original code and later be reused when the code cache is repopulated, yielding a transient execute-after-free primitive. This allows attackers to hijack transient control flow to newly generated code at obsolete offsets, bypassing software hardening...

Kiteworks on Monday said it worked with federal intelligence authorities over the weekend as it identified and addressed a critical security vulnerability during the scheduled precautionary shutdown . "During the shutdown, this activity led to the discovery of a previously unknown critical vulnerability confined to a capability that is enabled for less than 1% of the customer base," the company said in a statement. "Kiteworks developed and deployed a fix during the window, [and] applied an additional protective layer across all environments." There is no evidence that the vulnerability has ever been exploited in a malicious context. Other Kiteworks products are not affected by the flaw. The development comes days after Kiteworks, previously Accellion, urged customers to take their systems offline for a period of nine hours, in addition to shutting down environments it hosts on behalf of customers, after receiving intelligence about a potential imminent cybe...

Dutch authorities have confirmed that they arrested a 24-year-old man from Amsterdam in connection with the ShinyHunters group. "It is true that this month a 24-year-old man from Amsterdam was arrested in an investigation into the hacker group ShinyHunters," the Politie Landelijke Opsporing en Interventies said in an X post Monday. Police said the individual is expected to appear before the Rotterdam District Court on September 29, 2026. Although law enforcement officials did not disclose any additional details, independent security journalist Brian Krebs and DataBreaches.Net identified the arrested man as Pepijn van der Stap (aka Umbreon), who was previously apprehended in 2023 for his role in a series of data thefts and extortions. Per DataBreaches.Net, van der Stap was arrested on September 15, 2026. In 2023, it emerged that the individual worked at cybersecurity company Hadrian and volunteered at the Dutch Institute for Vulnerability Disclosure (DIVD). ...

A malicious MCP server could trick an application built on the official  MCP Python SDK  into handing over the OAuth credentials it uses to log in to a real service, the SDK's maintainers said in a security advisory. Affected versions sent the client secret, the authorization code, and the PKCE proof key to a token endpoint the attacker controlled. The fix is in versions 1.30.0 and 2.2.0. The Model Context Protocol (MCP) is an open standard for connecting AI applications to outside tools and data, and this package is its official Python SDK for building MCP servers and clients. With the stolen credentials, the attacker can request a valid access token from the real login service. Cycode, the security firm that reported the flaw , demonstrated that full exchange in a test and says the resulting token carries whatever permissions the app was granted. The client secret is long-lived, so it keeps working until it is changed. The flaw is rated high (7.5) for the two prov...

Apple has released security updates to address a vulnerability in older versions of iOS, iPadOS, and macOS that it said may have been exploited in targeted attacks. The vulnerability, tracked as CVE-2026-86950 , refers to an out-of-bounds write impacting the CoreGraphics component that could lead to arbitrary code execution when processing a maliciously crafted file. The iPhone maker said the issue was addressed with improved bounds checking. It credited Meta Product Security with discovering and reporting the issue. "Apple is aware of a report that this issue may have been exploited in an extremely sophisticated attack against specific targeted individuals on versions of iOS before iOS 27," it added. However, the company offered no details on how many individuals were targeted, if any of those attempts were successful, or when the first instance of CVE-2026-86950 exploitation occurred. The shortcoming has been addressed in the following devices and operating syste...

The attacker who stole about $388 million from the cryptocurrency exchange Bitget gained access through a vulnerability in a third-party security product the exchange used, Bitget said on Monday. The attacker exploited the flaw to obtain high-level internal credentials and then, on September 24, used them to send fraudulent withdrawal commands to Bitget's wallet system. Exchanges keep most customer funds in offline cold wallets and use hot and warm wallets to process withdrawals. Transfers from those wallets must still be approved before they are signed. The stolen funds came from part of Bitget's hot and warm wallets, and its cold wallets were not affected. Bitget  said last week  that a critical backend system in its wallet infrastructure had been compromised and used to spoof transaction data and trigger its approval process. It had not said how the attacker got in. Bitget CEO Gracy Chen described the attack on Monday in a livestream, in an interview with  The...

A domain used as harmless placeholder text showed up in roughly 1,700 repositories. Then somebody registered it and started serving malicious lures. That is the kind of week this was: forgotten assumptions turning into live attack surface. Elsewhere, weak service accounts, old bugs, exposed systems, phishing kits, and strangely easy exploit paths kept doing useful work for attackers. Nothing exotic. Mostly things nobody expected to matter anymore. Here’s the full recap of what mattered this week. ⚡ Threat of the Week Citrix Warns of Actively Exploited NetScaler ADC and Gateway Flaws — Citrix released patches to address multiple vulnerabilities, including CVE-2026-88771 and CVE-2026-88772, that have come under active exploitation. CVE-2026-88771 is an improper input validation vulnerability that could allow an unauthenticated attacker to execute arbitrary commands, while successful exploitation of CVE-2026-88772 could allow for remote code execution or denial-of-service. CISA...

The U.S. Cybersecurity and Infrastructure Security Agency (CISA) on Sunday added two critical Citrix NetScaler ADC and Gateway flaws to its Known Exploited Vulnerabilities ( KEV ) catalog, following reports of active exploitation. The vulnerabilities are listed below - CVE-2026-88771 (CVSS score: 9.5) - An improper input validation vulnerability that could allow an unauthenticated attacker to execute arbitrary commands.  CVE-2026-88772 (CVSS score: 9.5) - An improper restriction of operations within the bounds of a memory buffer vulnerability that could allow for remote code execution or denial-of-service. While CVE-2026-88771 affects all NetScaler ADC and NetScaler Gateway deployments, CVE-2026-88772 requires the DTLS configuration to be enabled on NetScaler ADC or NetScaler Gateway, an option that is turned on by default on VPN virtual servers. The relevant configuration is as follows - add vpn vserver vpn1 SSL 10.0.0.0 443 -Listenpolicy NONE 

Two critical vulnerabilities in Citrix NetScaler ADC and NetScaler Gateway that allow remote code execution have been exploited in the wild, Citrix confirmed on September 27. It released fixes for both, along with six other flaws. One of the two affects every deployment on an affected version, including those in the default configuration. The bulletin came a day after security firm watchTowr said two unpatched NetScaler RCE flaws had been exploited, and after some administrators said they had taken appliances offline. Citrix did not say whether its two flaws are the ones watchTowr described, but they match that account. NetScaler ADC and NetScaler Gateway sit at the edge of enterprise networks, where they handle VPN and remote access, load balancing, and user authentication. Citrix said in its bulletin that the two exploited flaws are: CVE-2026-88771 (CVSS v4 score: 9.5) - An improper input validation flaw that lets an unauthenticated attacker run arbitrary commands. It a...

The Psychedelic Stealer malware distributed via compromised Ukrainian websites using ClickFix-style Cloudflare verification checks is part of a wider malware-as-a-service (MaaS) platform called Lunex . The new findings come from Ontinue, which described the activity as a four-stage attack chain aimed at targeting Ukrainian-speaking users. "The attack chain begins with a fake CAPTCHA page and culminates in the deployment of a fully-featured C2 agent," Ontinue threat researcher Rhys Downing said in a technical report. "The stealer extracts credentials and data from seven Chromium-based browsers, exfiltrates cryptocurrency wallets, and establishes persistent remote filesystem access through a PowerShell-based Native Messaging Host installed within the victim's browser." The infection makes use of bogus MSI installers delivered via ClickFix to trigger a series of actions, including delivering a loader dubbed LunexLoader that's designed to bypass User Ac...

Google is warning of renewed mass exploitation of a known security vulnerability in Oracle PeopleSoft as part of a campaign targeting multiple sectors globally. The ShinyHunters-linked activity involves the weaponization of CVE-2026-35273 (CVSS score: 9.8), a critical security flaw that could result in unauthenticated remote code execution. The vulnerability was first exploited as a zero-day in attacks against academic institutions to conduct reconnaissance, deploy remote access software like MeshCentral agent for persistence, move laterally over SSH, run a shell script to connect via SSH to other internal PeopleSoft machines using known username/password combinations, and steal data. At that time, Google-owned Mandiant said it initiated notifications to over 100 global organizations whose IP addresses matched vulnerable endpoints, most of them located in the U.S. "This new wave of activity stems from UNC6240 modifying its exploit to bypass web application firewall (WAF...

Details have emerged about a high-severity security flaw in the Elementor Website Builder WordPress plugin that could be exploited by an unauthenticated attacker to create rogue administrator accounts and take control of a site. The cross-site request forgery (CSRF) vulnerability, which has yet to be assigned a CVE identifier, carries a CVSS score of 8.8 out of 10.0. It only affects versions 4.3.0 and 4.3.1 of the plugin, which is active on over 10 million WordPress sites. Statistics from WordPress.org show that the two impacted versions alone have been installed on more than 2 million sites. "One link, opened by a logged-in WordPress user, makes that user carry out any REST API action their account is permitted to perform," Patchstack said . "On a stock installation, an administrator clicking the link creates a second administrator account for the attacker." The WordPress security company said the attack does not hinge on any prerequisite, such as JavaScrip...

The U.S. Cybersecurity and Infrastructure Security Agency (CISA) on Friday added two security flaws impacting Microsoft SharePoint and Mikrotik RouterOS to its Known Exploited Vulnerabilities ( KEV ) catalog, citing evidence of active exploitation. The vulnerabilities in question are as follows - CVE-2026-65660 (CVSS score: 8.8) - A code injection vulnerability in Microsoft Office SharePoint that allows an authorized attacker to execute code over a network. CVE-2026-67279 (CVSS score: 6.9) - An improper enforcement of behavioral workflow vulnerability in  Mikrotik RouterOS that could allow an unauthenticated client to open a session channel and send an exec request. As reported by The Hacker News earlier this week, CVE-2026-65660 was originally described by Microsoft as a spoofing vulnerability impacting SharePoint Server. The tech giant has since updated the advisory to state that it could be abused to obtain remote code execution. "As of 9/25/2026, Microsoft ...

Kiteworks (formerly Accellion) is urging customers to shut down their systems as a precautionary measure for nine hours over the weekend after it received threat intelligence about an imminent cyber attack. "Kiteworks received credible threat intelligence from federal intelligence authorities indicating that a threat actor may attempt to target some Kiteworks systems," said Frank Balonis, Chief Information Security Officer (CISO) at Kiteworks. "Out of an abundance of caution, we notified customers directly and recommended a precautionary shutdown window while we continue to work through the matter with federal intelligence authorities." The company said it has not found any evidence that its customers' systems have been compromised, emphasizing the advisory is preventative rather than a response to a confirmed hack. The development was first reported by German news publication Heise. Kiteworks did not disclose which law enforcement agency alerted the ...

The Canadian Centre for Cyber Security has warned that a now-patched Roundcube Webmail vulnerability is being actively exploited in the wild. The vulnerability in question is CVE-2026-48842 (CVSS score: 8.1), a pre-authentication SQL injection in the virtuser_query plugin of Roundcube Webmail versions 1.6.x before 1.6.16 and 1.7.x before 1.7.1. The issue stems from a preg_replace() backslash escape bypass that allows attackers to inject arbitrary SQL statements without authentication. "Unauthenticated attackers can inject SQL into Roundcube's database backend through the virtuser_query plugin, potentially exposing mail account credentials and stored messages," SentinelOne said . Patches for the vulnerability were released by Roundcube in May 2026 as part of 1.6.16 and 1.7.1. In an update shared this week, the Cyber Centre said the security flaw is being actively exploited in the wild, citing open-source reporting. No additional details of the exploitation ac...

A flaw in Cloudflare Containers let a paying customer read data that other customers' containers had left behind on the same server, Cloudflare and the researchers who found it said on Thursday. The data came from disk space that earlier containers had used and given up, not from any live workload, and an attacker could not choose whose data they got,  according to Cloudflare . The company has fixed the flaw across its service and says customers need to do nothing. Cloudflare Containers runs customers' programs inside containers on servers shared by many accounts, and Cloudflare, not the customer, picks the server. Cloudflare Sandboxes, which runs on Containers and is sold as a safe place to run untrusted code, including code written by AI agents, was affected too. The flaw was reported on September 4 by Oren Yomtov of the security firm Accomplish , through Cloudflare's bug bounty program. The problem was in how the shared disks were set up. Each container gets a ...

The U.S. Cybersecurity and Infrastructure Security Agency (CISA), on Thursday, added two critical security flaws impacting WSO2 and Adobe Commerce and Magento to its Known Exploited Vulnerabilities ( KEV ) catalog, based on evidence of active exploitation. The vulnerabilities are listed below - CVE-2026-5430 (CVS score: 9.8) - A path traversal vulnerability in  WSO2 API Control Plane, API Manager, Traffic Manager and Universal Gateway that could allow unrestricted file upload and lead to remote code execution. CVE-2026-71362 (CVSS score: 9.1) - An incorrect authorization vulnerability in  Adobe Commerce and Magento that could allow an attacker to leverage this vulnerability to gain elevated access to sensitive resources without any user interaction. The addition of CVE-2026-5430 to the KEV comes a little over a week after watchTowr said it's seeing in-the-wild exploitation efforts against its honeypots since at least September 13, 2026. "We captured forged JW...