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CISA Warns of Citrix NetScaler Authentication Bypass Vulnerability Exploited in Attacks

CISA adds exploited Citrix NetScaler authentication bypass CVE-2026-19490 to the KEV catalog; federal agencies must patch by September 12.

CISA added CVE-2026-19490, a CWE-288 authentication bypass affecting NetScaler ADC and Gateway deployments configured as AAA virtual servers or Gateway services (including SSL VPN, ICA Proxy, and RDP Proxy), to the Known Exploited Vulnerabilities catalog. Citrix released fixes on August 19, 2026; honeypots recorded 56 attack attempts between September 3 and 8 after a public PoC, though no confirmed production compromises have been reported. Affected builds include 14.1 before 14.1-73.32 and 13.1 before 13.1-63.21; newer installations require SAML IdP configuration to be exposed.

Cyber Security Newsupdated · 5d agofirst · 5d agoExploit / PoC in the wild 5 sourcesCVE-2026-19490

AL26-019 - Vulnerabilities impacting Citrix NetScaler ADC and NetScaler Gateway - CVE-2026-19490 and CVE-2026-19489

Canadian Cyber Centre alerts on Citrix NetScaler ADC/Gateway flaws CVE-2026-19490 (authentication bypass) and CVE-2026-19489 (buffer overflow), urging emergency patching.

The Canadian Centre for Cyber Security issued alert AL26-019 covering two Citrix NetScaler vulnerabilities disclosed in a vendor advisory on August 19, 2026. CVE-2026-19490 (CWE-288) allows a remote unauthenticated attacker to bypass authentication on appliances configured as a Gateway for SSL VPN, ICA Proxy, CVPN, RDP Proxy, or as an AAA virtual server. CVE-2026-19489 (CWE-120) is a classic buffer overflow that may cause memory overflow, unpredictable behavior, or denial-of-service conditions. Affected appliances are vulnerable when configured as a SAML IdP; fixed versions include 14.1-73.32, 13.1-63.21, and 13.1-37.277 for FIPS.

Citrix urges customers to fix critical NetScaler authentication bypass (CVE-2026-19490)

Citrix patched a critical authentication bypass, CVE-2026-19490, in NetScaler Gateway and NetScaler ADC, urging customers to upgrade immediately.

Citrix has patched two flaws in NetScaler ADC and NetScaler Gateway. CVE-2026-19490 is a critical authentication bypass (CVSS v4.0 9.3) that works when the appliance is configured as an SSL VPN, ICA Proxy, CVPN, RDP Proxy Gateway or AAA virtual server, with additional conditions depending on firmware and SAML configuration. A second flaw, CVE-2026-19489 (CVSS 8.8), is a memory overflow that can cause denial of service when SIP ALG is enabled on LSN setups. Rapid7 had not observed exploitation as of August 19, 2026, but urged emergency patching; a signature-based mitigation is available via NetScaler Console.

Previously patched Citrix NetScaler flaw exploited in the wild (CVE-2026-8452)

Actively exploited Citrix NetScaler flaw CVE-2026-8452, patched in June, now added to CISA KEV; attackers deploy web shells and run discovery commands.

CISA added CVE-2026-8452, a memory overflow vulnerability in Citrix NetScaler ADC/Gateway, to its Known Exploited Vulnerabilities catalog on August 26, 2026, giving federal agencies until August 29 to remediate. Citrix disclosed and patched the flaw on June 30, 2026 in versions 14.1-72.61, 13.1-63.18, and 13.1-37.272. watchTowr Labs found the flaw can be chained into unauthenticated remote code execution and released a PoC on August 14. Previdian and Defused reported exploitation with web shells named x.php and z.php from at least three unique source IPs.

Help Net Security · 20d agoExploit / PoC in the wildCVE-2026-8452CVE-2015-3246CVE-2015-5287+3 CVEs

Citrix security advisory (AV26-645) – Update 3

Canada's Cyber Centre updates Citrix advisory as CVE-2026-8451 and CVE-2026-8452 in NetScaler ADC/Gateway are confirmed exploited in the wild.

The Canadian Centre for Cyber Security updated advisory AV26-645 on August 26, 2026, covering critical vulnerabilities in Citrix NetScaler ADC and Gateway (versions 14.1 before 14.1-72.61 and 13.1 before 13.1-63.18, plus FIPS builds). Open-source reporting indicates CVE-2026-8451 and CVE-2026-8452 are being exploited in the wild. Update 3 references related CISA action, and patched builds were released starting June 30, 2026.

CVE-2026-19490: Critical Vulnerability Affecting Citrix NetScaler ADC and NetScaler Gateway

CVE-2026-19490 is a critical unauthenticated authentication bypass in Citrix NetScaler ADC and Gateway, remotely exploitable without user interaction.

An advisory published August 19, 2026 describes CVE-2026-19490, a critical authentication bypass affecting Citrix NetScaler ADC and NetScaler Gateway. The flaw carries a CVSS v4.0 base score of 9.3 and is remotely exploitable by unauthenticated attackers over the network without user interaction or elevated privileges. NetScaler ADC and Gateway are widely deployed enterprise products positioned at or near the network perimeter, providing load balancing, SSL/TLS offloading, and secure remote access. The text does not state whether exploitation has been observed in the wild.

Rapid7 Blog · 27d agoVulnerabilityCVE-2026-194901

You’re Back In The Room (Citrix NetScaler Pre-Auth RCE CVE-2026-8452(?))

watchTowr Labs details a pre-authentication remote code execution flaw, tracked as CVE-2026-8452, in Citrix NetScaler appliances.

watchTowr Labs published technical analysis of a pre-authentication remote code execution vulnerability in Citrix NetScaler, tentatively assigned CVE-2026-8452. The CVE identifier is marked as provisional in the write-up. No confirmation of in-the-wild exploitation is provided in the available text.

watchTowr Labs · Aug 14, 2026Exploit / PoCCVE-2026-8452

Exploits in the Wild for Citrix ADC and Citrix Gateway Directory Traversal Vulnerability CVE-2019

Unit 42 confirmed in-the-wild exploitation of CVE-2019-19781, a critical Citrix ADC/Gateway directory traversal flaw enabling unauthenticated file access and RCE.

CVE-2019-19781, a CVSS 9.8 directory traversal vulnerability, affects all supported versions of Citrix ADC and Citrix Gateway. Unit 42 captured multiple exploitation attempts in the wild and identified scanning activity from roughly 700 Shodan-exposed hosts. The flaw stems from improper pathname handling in Apache, allowing unauthenticated attackers to read sensitive files like smb.conf or achieve remote code execution via crafted XML. Palo Alto Networks released Threat Prevention signatures 57497 and 57570 on January 7, 2020, while Citrix published advisories CTX267027 and CTX267679 with responder policy mitigations pending a late-January patch.

Palo Alto Unit 42 · 29d agoExploit / PoC in the wildCVE-2019-19781

Critical NetScaler Flaw Can Bypass Authentication on Certain Gateway and AAA Servers

Citrix patches critical NetScaler Gateway and AAA authentication bypass CVE-2026-19490 (CVSS 9.3) plus a SIP ALG memory overflow flaw; exploitation attempts observed.

Citrix fixed CVE-2026-19490 (CVSS 9.3), an authentication bypass affecting customer-managed NetScaler ADC and Gateway appliances configured as Gateway (SSL VPN, ICA Proxy, CVPN, RDP Proxy) or AAA virtual servers, and CVE-2026-19489 (CVSS 8.8), a memory overflow causing DoS when SIP ALG is enabled in Large Scale NAT groups. Updates are available in versions 14.1-73.32, 13.1-63.21, and corresponding FIPS/NDcPP builds, while Citrix-managed cloud services were already patched. The flaws were reported by Samarth Vashisht of JPMorgan Chase's penetration-testing team, and Previdian later observed 10 exploitation attempts against CVE-2026-19490 from six unique IP addresses in Australia, Germany, Japan, and the US, with no confirmed compromise.

Week in review: Compromised Zimbra servers, previously patched Citrix NetScaler flaw exploited

Help Net Security's weekly digest highlights 274 compromised Zimbra servers, Gitea and Citrix NetScaler KEV additions, a PaperCut zero-day, and a suspected Iran-linked power plant attack.

The roundup reports at least 274 internet-facing Zimbra instances compromised via CVE-2026-73570, critical Gitea CVE-2026-60004 added to CISA's KEV catalog after exploitation began, and previously patched Citrix NetScaler flaw CVE-2026-8452 exploited in the wild. It also covers PaperCut NG/MF zero-day attacks, a suspected Iran-linked shutdown of a UK power plant, an FBI seizure of domains tied to a China-linked group that hit NASA, DOJ and the Senate, a cyberattack disrupting Boston Scientific, and the Manchester Airports Group breach. Additional items include Chameleon SEO poisoning phishing, Android car head unit proxy botnet malware, ReliaQuest social engineering by ShinyHunters, fake OpenAI Codex macOS malware, and AI-related workforce and supply chain interviews.

U.S. CISA adds Red Hat, Linux Kernel, Ajax.NET Professional, Microsoft SQL Server, and Citrix NetScaler flaws to its Known Exploited Vulnerabilities catalog

CISA added six flaws, including actively exploited CVE-2026-8452 in Citrix NetScaler, to its Known Exploited Vulnerabilities catalog with federal patch deadlines.

CISA added six vulnerabilities to its KEV catalog: CVE-2015-3246 and CVE-2015-5287 (Red Hat libuser race condition and ABRT privilege escalation), CVE-2019-1068 (Microsoft SQL Server RCE), CVE-2021-23758 (Ajax.NET Professional deserialization), CVE-2022-0995 (Linux Kernel out-of-bounds write) and CVE-2026-8452 (Citrix NetScaler ADC/Gateway memory buffer flaw). CVE-2026-8452 has been observed under active exploitation in the wild and can cause denial-of-service. Under BOD 22-01, federal civilian agencies must patch CVE-2019-1068 and CVE-2026-8452 by August 29, 2026, and the rest by September 9, 2026.

Security Affairs · 19d agoExploit / PoC in the wildCVE-2015-3246CVE-2015-5287CVE-2019-1068+3 CVEs

Threat Matrix: Mapping threats across cloud web applications

Microsoft released a Cloud Web Applications Threat Matrix, a MITRE ATT&CK-aligned framework mapping threats to cloud-hosted web apps and serverless platforms.

Microsoft introduced the cloud web applications threat matrix, which organizes attack techniques for cloud-hosted web apps and serverless platforms using MITRE ATT&CK tactics, from resource development through impact. The framework covers attack paths spanning application code, managed runtimes, workload identities, and deployment pipelines, cataloging techniques such as subdomain takeover, code injection in connected repositories, compromised registry images, exposed admin interfaces, and serverless trigger injection. It builds on Microsoft's earlier Kubernetes and storage services matrices to help defenders identify visibility gaps, prioritize hardening, and plan investigations in cloud-native environments.

Microsoft Security Blog · 6d agoTools

CISA Warns of Six Exploited Flaws in Microsoft, Linux, Red Hat and Citrix Products

CISA added six actively exploited vulnerabilities in Microsoft, Linux, Red Hat and Citrix products to its KEV catalog on August 26.

CISA added six new vulnerabilities to its Known Exploited Vulnerabilities catalog on August 26, citing signs of active exploitation in the wild. The affected products span Microsoft, Linux, Red Hat, and Citrix. Specific CVE identifiers and affected versions were not listed in the source text, but KEV listing requires confirmed exploitation.

Infosecurity Magazine · 20d agoExploit / PoC in the wild

Pyramid Solutions NetStaX EtherNet/IP Stack

CISA flags critical CVE-2026-78012 (CVSS 9.8) stack buffer overflow in Pyramid Solutions NetStaX EtherNet/IP stacks below v5.6.1, risking crashes or remote attack vectors.

CISA republished Pyramid Solutions' advisory for CVE-2026-78012, a CWE-121 stack-based buffer overflow in the NetStaX EtherNet/IP stack versions prior to 5.6.1, scored CVSS 9.8. Large Class 3 explicit-message requests can exceed the application-side receive buffer without generating a CIP error, potentially causing memory corruption, device crashes, or a silent remote attack vector. All eight adapter and scanner DLL/development kit variants, including CIP Security editions, are affected across critical manufacturing, energy, water, and chemical sectors. No public exploitation has been reported.

CISA Advisories · 12d agoAdvisoryCVE-2026-78012

CISA Adds Four Known Exploited Vulnerabilities to Catalog

CISA added four actively exploited vulnerabilities—Fortinet buffer overflow, Citrix NetScaler and Cisco auth bypasses, and a Chromium V8 write—to the KEV Catalog.

CISA added CVE-2025-25249 (Fortinet heap-based buffer overflow), CVE-2026-19490 (Citrix NetScaler authentication bypass), CVE-2026-87491 (Google Chromium V8 out-of-bounds write), and CVE-2026-20079 (Cisco Firewall Management Center authentication bypass) to its Known Exploited Vulnerabilities Catalog based on evidence of active exploitation. Under Binding Operational Directive 26-04, Federal Civilian Executive Branch agencies must prioritize rapid remediation of these high-risk vulnerabilities on exposed assets and verify whether systems were compromised before patching. CISA encourages all organizations to adopt risk-based vulnerability management and prioritize KEV Catalog remediation.

CISA Advisories · 6d agoExploit / PoC in the wildCVE-2025-25249CVE-2026-19490CVE-2026-87491+1 CVEs

Top 10 Best Multi-Cloud Security Platforms in 2026

An editorial roundup of the ten best multi-cloud security platforms for 2026, split between CNAPPs (Wiz, Prisma Cloud) and cloud-networking security (Aviatrix).

The article frames multi-cloud security as two markets: CNAPP platforms (Wiz, Prisma Cloud, CrowdStrike, Orca, Defender) securing what runs in clouds, and cloud-networking-security platforms (Aviatrix) securing how clouds connect. It ranks ten platforms including Palo Alto Prisma Cloud for breadth, Wiz for correlation, Check Point CloudGuard, Fortinet, Aviatrix, Microsoft Defender for Cloud, Trend Micro, and CrowdStrike. It flags the ~$32 billion Google–Wiz acquisition as raising cloud-neutrality questions buyers should address contractually.

Cyber Security News · 2h agoTools

Cisco security advisory (AV26-876)

Canada's Cyber Centre relayed Cisco advisories covering a Nexus 9000 Silicon One RCE, IOS XR hardening, and denial-of-service flaws across IP phone lines.

The Canadian Centre for Cyber Security advisory AV26-876 lists Cisco vulnerabilities affecting IOS XR, Nexus 9000 Series switches, and several IP phone series. Included are a Nexus 9000 Silicon One remote code execution vulnerability, a September 2026 IOS XR security hardening release, and SIP software denial-of-service flaws in Desk Phone 9800, IP Phone 7800/8800, and Video Phone 8875. The Cyber Centre urges users and administrators to review the Cisco advisories and apply updates as they become available. No active exploitation is reported in the advisory.

Canadian Centre for Cyber Security · 12d agoAdvisory

The push to designate AI as the next critical infrastructure sector

Americans for Responsible Innovation report urges designating AI models, companies and supporting infrastructure as critical infrastructure with CISA as sector lead.

A report from the nonprofit Americans for Responsible Innovation calls for the federal government to declare the AI sector — including frontier model designs, model weights, datacenters, AI hardware and semiconductors — the 17th critical infrastructure sector, with CISA as the lead agency for sector cyberthreats. The authors argue AI is concentrated among a handful of foundation models and interdependent with other sectors, so a single attack on the AI stack could cascade widely, citing incidents like Iranian drone attacks on Amazon datacenters. Former DHS officials note the designation would unlock federal resources such as CDM access and threat intelligence, but warn that picking a lead agency could trigger a bureaucratic turf war with Commerce and Treasury.

CyberScoop · 26d agoAI policy

Palo Alto Networks security advisory (AV26-905)

Canada's Cyber Centre relayed Palo Alto Networks advisories covering PAN-OS, Cloud NGFW, Prisma Access, and Prisma Browser vulnerabilities, including PAN-OS CVE-2026-0310 buffer overflow.

The Canadian Centre for Cyber Security issued advisory AV26-905, noting that as of September 10, 2026, multiple Palo Alto Networks products are affected by vulnerabilities. Affected products include Cloud NGFW on AWS and Azure, multiple PAN-OS versions, Prisma Access, and Prisma Browser prior to 151.26.5.170. The advisory references CVE-2026-0310, a PAN-OS buffer overflow via XML processing (PAN-SA-2026-0012), and the September 2026 Chromium monthly vulnerability update. Administrators are encouraged to review the vendor links and apply available updates.

CISA Urges Service Providers to Provide Transparent Updates During Major IT and OT Outages

CISA and FBI issued guidance urging service providers to deliver timely, transparent communications during major IT and OT outages.

CISA, with the FBI and international partners, released 'Communicating Under Pressure: Best Practices for Service Providers', urging providers to prepare crisis-communication procedures, provide timely status updates during IT/OT outages, and maintain out-of-band communication channels. The guidance warns that disruptions to telecom, cloud, energy, and water services can cascade across critical infrastructure. It aligns with CISA's CI Fortify initiative supporting IT/OT isolation and recovery.

GBHackers · 5d agoAdvisory

A Graph-Based Approach for Mapping Kernel-Level Telemetry to MITRE ATT&CK

Trace2ATT&CK maps eBPF kernel telemetry to MITRE ATT&CK via provenance graphs and RAG with local open-weights LLMs, validated on 347 Atomic Red Team tests.

Trace2ATT&CK collects kernel-level events via eBPF, correlates attacker commands into a provenance graph, and derives compact graph representations suitable for LLM-based reasoning, mapping behavior to MITRE ATT&CK techniques with ranked candidates and rationales. Mapping uses both pure LLM prompting and retrieval-augmented generation grounded in the ATT&CK knowledge base. It was evaluated on 347 Linux Atomic Red Team tests using locally deployed open-weights LLMs. RAG consistently improved ATT&CK mapping over pure prompting, and provenance graphs substantially outperformed raw telemetry, without compromising data confidentiality.

arXiv cs.CR · 4d agoResearch

Critical Dell ObjectScale Vulnerabilities Allows Malicious Users to Compromise the Affected system

Dell's DSA-2026-393 fixes ObjectScale/ECS flaws including unauthenticated deserialization RCE CVE-2026-70416 rated CVSS 10.0.

Dell advisory DSA-2026-393 (September 10, 2026) covers multiple flaws in ObjectScale and Elastic Cloud Storage (ECS). CVE-2026-70416 is a critical untrusted-data deserialization RCE (CVSS 10.0) in ObjectScale before 4.4.0.0 allowing unauthenticated remote code execution and full environment takeover, credited to researcher WinD39 (Huynh Dinh Vu). Additional issues include CVE-2025-43936 improper authentication (8.1), CVE-2026-26947 privilege management (6.7), CVE-2026-36591-style weak crypto CVE-2025-36591 (4.4), CVE-2026-76104 permission assignment DoS (5.5), plus third-party CVEs in Apache Log4j, liblzma, and the Linux kernel. Dell advises upgrading to version 4.4.0.0 or later (or 4.2.0.1) and restricting management interfaces until patched.

CISA Red Team Fully Compromised Two Critical Infrastructure Orgs

CISA red teams achieved full domain and cloud compromise at two critical infrastructure orgs; one SOC never detected the intrusion.

CISA advisory AA26-237A documents two simultaneous red team assessments. Organization A (Government Services sector) missed the intrusion entirely, as default credentials on a web app, ADCS ESC1 abuse, and thousands of false-positive alerts let the red team reach sensitive business systems and read SOC email. Organization B (Water/Wastewater sector) detected, isolated, and reimaged hosts quickly, but both orgs lacked Conditional Access for workload identities, and B still exposed DCSync, Golden Ticket, and OT network attack paths.

Security Affairs · 20d agoAdvisory1