Citrix | Breaking Cybersecurity News | The Hacker News

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...

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...

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...

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 U.S. Cybersecurity and Infrastructure Security Agency (CISA) on Wednesday added three flaws, each impacting Cisco, Citrix, and Fortinet, to its Known Exploited Vulnerabilities ( KEV ) catalog, requiring Federal Civilian Executive Branch (FCEB) agencies to apply the patches by September 12, 2026. The vulnerabilities are listed below - CVE-2026-20079 (CVSS score: 10.0) - An authentication bypass vulnerability in the web interface of Cisco Secure Firewall Management Center (FMC) Software that could allow an unauthenticated, remote attacker to bypass authentication and execute script files on an affected device to obtain root access to the underlying operating system. CVE-2026-19490 (CVSS score: 9.3) - An authentication bypass vulnerability in  Citrix NetScaler ADC and NetScaler Gateway when the appliance is configured as an AAA virtual server or as a Gateway (SSL VPN, ICA Proxy, CVPN, or RDP Proxy). CVE-2025-25249 (CVSS score: 7.3) - A heap-based buffer overflow ...

Citrix has released updates to address two security flaws impacting NetScaler ADC and NetScaler Gateway deployments, including a critical-severity authentication bypass vulnerability. According to the cloud computing and virtualization technology company, the issues affect customer-managed NetScaler ADC and NetScaler Gateway, including certain FIPS and NDcPP builds, as well as SecurAccess ZTNA Hybrid deployments that use customer-managed NetScaler instances. It bears noting that the vulnerabilities do not apply to Citrix-managed cloud services or Citrix-managed Adaptive Authentication, as the necessary updates have already been applied. The list of impacted NetScaler versions is below - NetScaler ADC and NetScaler Gateway 14.1 BEFORE 14.1-73.32  NetScaler ADC and NetScaler Gateway 13.1 BEFORE 13.1-63.21  NetScaler ADC FIPS BEFORE 14.1-73.32 FIPS  NetScaler ADC FIPS and NDcPP BEFORE 13.1-37.277  The first of the two vulnerabilities is CVE-2026...

Threat actors associated with the Anubis ransomware operation have been observed exploiting the Citrix Bleed 2 (CVE-2025-5777) vulnerability to obtain initial access. "Although tactics differ between affiliates, common patterns emerged in tradecraft through use of legitimate Remote Management and Monitoring (RMM) tooling, credential access, and hands-on-keyboard procedures used for lateral movement," Arctic Wolf said in a report published this week. "Anubis affiliates repeatedly abused legitimate remote access and administration tools, including ScreenConnect, Zoho Assist, MeshAgent, Remotely, UltraVNC, and Total Software Deployment, to blend in with normal IT activity while maintaining control of victim systems." Anubis is a ransomware-as-a-service (RaaS) group that first emerged in late 2024 as a rebrand of Sphinx ransomware. The ransomware operation was formally announced on the Ransomware and Advanced Malware Protection (RAMP) underground forum in Febr...

Citrix on Tuesday released security updates to address multiple flaws in NetScaler ADC (formerly Citrix ADC) and NetScaler Gateway (formerly Citrix Gateway) that could be exploited by an attacker to facilitate arbitrary file reads or trigger a denial-of-service (DoS) condition. The vulnerabilities are listed below - CVE-2026-8451 (CVSS score: 8.8) - An insufficient input validation vulnerability leading to memory overread when NetScaler ADC or NetScaler Gateway is configured as a SAML IDP CVE-2026-8452 (CVSS score: 8.8) - A memory overflow vulnerability leading to unpredictable or erroneous behavior and denial-of-service when the appliance is configured as a Gateway or an AAA virtual server CVE-2026-8655 (CVSS score: 8.8) - Multiple memory overflow vulnerabilities leading to unpredictable or erroneous behavior and denial-of-service when NetScaler ADC is configured as an LB of type Oracle, a DNS Proxy, or a DNS recursive resolver deployment CVE-2026-10816 (CVSS sco...

A recently disclosed critical security flaw impacting Citrix NetScaler ADC and NetScaler Gateway is witnessing active reconnaissance activity, according to Defused Cyber and watchTowr . The vulnerability, CVE-2026-3055 (CVSS score: 9.3), refers to a case of insufficient input validation leading to memory overread, which an attacker could exploit to leak potentially sensitive information. Per Citrix, successful exploitation of the flaw hinges on the appliance being configured as a SAML Identity Provider (SAML IDP). "We are now observing auth method fingerprinting activity against NetScaler ADC/Gateway in the wild," Defused Cyber said in a post on X. "Attackers are probing /cgi/GetAuthMethods to enumerate enabled authentication flows in our Citrix honeypots." This is likely an attempt on the part of threat actors to determine if NetScaler ADC and NetScaler Gateway are indeed configured as a SAML IDP. In a similar warning, watchTowr said it has detected active...

Citrix has released security updates to address two vulnerabilities in NetScaler ADC and NetScaler Gateway, including a critical flaw that could be exploited to leak sensitive data from the application. The vulnerabilities are listed below - CVE-2026-3055 (CVSS score: 9.3) - Insufficient input validation leading to memory overread CVE-2026-4368 (CVSS score: 7.7) - Race condition leading to user session mixup Cybersecurity company Rapid7 said that CVE-2026-3055 refers to an out-of-bounds read that could be exploited by unauthenticated remote attackers to leak potentially sensitive information from the appliance's memory. However, for exploitation to be successful, the Citrix ADC or Citrix Gateway appliance must be configured as a SAML Identity Provider (SAML IDP), which means default configurations are unaffected. To determine if the device has been configured as a SAML IDP Profile, Citrix is urging customers to inspect their NetScaler Configuration for the specified st...

Amazon's threat intelligence team on Wednesday disclosed that it observed an advanced threat actor exploiting two then-zero-day security flaws in Cisco Identity Service Engine (ISE) and Citrix NetScaler ADC products as part of attacks designed to deliver custom malware. "This discovery highlights the trend of threat actors focusing on critical identity and network access control infrastructure – the systems enterprises rely on to enforce security policies and manage authentication across their networks," CJ Moses, CISO of Amazon Integrated Security, said in a report shared with The Hacker News. The attacks were flagged by its MadPot honeypot network, with the activity weaponizing the following two vulnerabilities - CVE-2025-5777 or Citrix Bleed 2 (CVSS score: 9.3) - An insufficient input validation vulnerability in Citrix NetScaler ADC and Gateway that could be exploited by an attacker to bypass authentication. (Fixed by Citrix in June 2025 ) CVE-2025-20337 (CV...

A European telecommunications organization is said to have been targeted by a threat actor that aligns with a China-nexus cyber espionage group known as Salt Typhoon . The organization, per Darktrace , was targeted in the first week of July 2025, with the attackers exploiting a Citrix NetScaler Gateway appliance to obtain initial access. Salt Typhoon, also known as Earth Estries, FamousSparrow, GhostEmperor, and UNC5807, is the name given to an advanced persistent threat actor with ties to China. Known to be active since 2019, the group gained prominence last year following its attacks on telecommunications services providers, energy networks, and government systems in the U.S. The adversary has a track record of exploiting security flaws in edge devices, maintaining deep persistence, and exfiltrating sensitive data from victims in more than 80 countries across North America, Europe, the Middle East, and Africa. In the incident observed against the European telecommunications enti...

Threat actors are attempting to leverage a newly released artificial intelligence (AI) offensive security tool called HexStrike AI to exploit recently disclosed security flaws. HexStrike AI, according to its website , is pitched as an AI‑driven security platform to automate reconnaissance and vulnerability discovery with an aim to accelerate authorized red teaming operations, bug bounty hunting, and capture the flag (CTF) challenges. Per information shared on its GitHub repository, the open-source platform integrates with over 150 security tools to facilitate network reconnaissance, web application security testing, reverse engineering, and cloud security. It also supports dozens of specialized AI agents that are fine-tuned for vulnerability intelligence, exploit development, attack chain discovery, and error handling. But according to a report from Check Point, threat actors are trying their hands on the tool to gain an adversarial advantage, attempting to weaponize the tool to ...

Citrix has released fixes to address three security flaws in NetScaler ADC and NetScaler Gateway, including one that it said has been actively exploited in the wild. The vulnerabilities in question are listed below - CVE-2025-7775 (CVSS score: 9.2) - Memory overflow vulnerability leading to Remote Code Execution and/or Denial-of-Service CVE-2025-7776 (CVSS score: 8.8) - Memory overflow vulnerability leading to unpredictable or erroneous behavior and Denial-of-Service CVE-2025-8424 (CVSS score: 8.7) - Improper access control on the NetScaler Management Interface The company acknowledged that "exploits of CVE-2025-7775 on unmitigated appliances have been observed," but stopped short of sharing additional details. However, for the flaws to be exploited, there are a number of prerequisites - CVE-2025-7775 - NetScaler must be configured as Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) or AAA virtual server; NetScaler ADC and NetScaler Gateway 13.1, 14.1...

The U.S. Cybersecurity and Infrastructure Security Agency (CISA) on Monday added three security flaws impacting Citrix Session Recording and Git to its Known Exploited Vulnerabilities ( KEV ) catalog, based on evidence of active exploitation. The list of vulnerabilities is as follows - CVE-2024-8068 (CVSS score: 5.1) - An improper privilege management vulnerability in Citrix Session Recording that could allow for privilege escalation to NetworkService Account access when an attacker is an authenticated user in the same Windows Active Directory domain as the session recording server domain CVE-2024-8069 (CVSS score: 5.1) - A deserialization of untrusted data vulnerability in Citrix Session Recording that allows limited remote code execution with the privileges of a NetworkService Account access when an attacker is an authenticated user on the same intranet as the session recording server CVE-2025-48384 (CVSS score: 8.1) - A link following vulnerability in Git that arises as a ...

The Dutch National Cyber Security Centre (NCSC-NL) has warned of cyber attacks exploiting a recently disclosed critical security flaw impacting Citrix NetScaler ADC products to breach organizations in the country. The NCSC-NL said it discovered the exploitation of CVE-2025-6543 targeting several critical organizations within the Netherlands, and that investigations are ongoing to determine the extent of the impact. CVE-2025-6543 (CVSS score: 9.2) is a critical security vulnerability in NetScaler ADC that results in unintended control flow and denial-of-service (DoS) when the devices are configured as a Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) OR AAA virtual server. The vulnerability was first disclosed in late June 2025, with patches released in the following versions - NetScaler ADC and NetScaler Gateway 14.1 prior to 14.1-47.46 NetScaler ADC and NetScaler Gateway 13.1 prior to 13.1-59.19 NetScaler ADC 13.1-FIPS and NDcPP prior to 13.1-37.236-FIPS and NDcPP ...

The U.S. Cybersecurity and Infrastructure Security Agency (CISA) on Thursday added a critical security flaw impacting Citrix NetScaler ADC and Gateway to its Known Exploited Vulnerabilities ( KEV ) catalog, officially confirming the vulnerability has been weaponized in the wild. The shortcoming in question is CVE-2025-5777 (CVSS score: 9.3), an instance of insufficient input validation that could be exploited by an attacker to bypass authentication when the appliance is configured as a Gateway or AAA virtual server. It's also called Citrix Bleed 2 owing to its similarities with Citrix Bleed (CVE-2023-4966). "Citrix NetScaler ADC and Gateway contain an out-of-bounds read vulnerability due to insufficient input validation," the agency said. "This vulnerability can lead to memory overread when the NetScaler is configured as a Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) OR AAA virtual server." CISA pointed out that flaws like CVE-2025-5777 are f...

The U.S. Cybersecurity and Infrastructure Security Agency (CISA) on Monday added four security flaws to its Known Exploited Vulnerabilities ( KEV ) catalog, citing evidence of active exploitation in the wild. The list of flaws is as follows - CVE-2014-3931 (CVSS score: 9.8) - A buffer overflow vulnerability in Multi-Router Looking Glass (MRLG) that could allow remote attackers to cause an arbitrary memory write and memory corruption CVE-2016-10033 (CVSS score: 9.8) - A command injection vulnerability in PHPMailer that could allow an attacker to execute arbitrary code within the context of the application or result in a denial-of-service (DoS) condition CVE-2019-5418 (CVSS score: 7.5) - A path traversal vulnerability in Ruby on Rails' Action View that could cause contents of arbitrary files on the target system's file system to be exposed CVE-2019-9621 (CVSS score: 7.5) - A Server-Side Request Forgery (SSRF) vulnerability in the Zimbra Collaboration Suite that could ...

Citrix has released security updates to address a critical flaw affecting NetScaler ADC that it said has been exploited in the wild. The vulnerability, tracked as CVE-2025-6543 , carries a CVSS score of 9.2 out of a maximum of 10.0. It has been described as a case of memory overflow that could result in unintended control flow and denial-of-service. However, successful exploitation requires the appliance to be configured as a Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) or AAA virtual server. The shortcoming impacts the below versions - NetScaler ADC and NetScaler Gateway 14.1 prior to 14.1-47.46  NetScaler ADC and NetScaler Gateway 13.1 prior to 13.1-59.19 NetScaler ADC and NetScaler Gateway 12.1 and 13.0 (vulnerable and end-of-life) NetScaler ADC 13.1-FIPS and NDcPP prior to 13.1-37.236-FIPS and NDcPP "Secure Private Access on-prem or Secure Private Access Hybrid deployments using NetScaler instances are also affected by the vulnerabilities," Citrix ...