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Microsoft on Monday issued out-of-band security patches for a high-severity Microsoft Office zero-day vulnerability exploited in attacks. The vulnerability, tracked as CVE-2026-21509 , carries a CVSS score of 7.8 out of 10.0. It has been described as a security feature bypass in Microsoft Office. "Reliance on untrusted inputs in a security decision in Microsoft Office allows an unauthorized attacker to bypass a security feature locally," the tech giant said in an advisory. "This update addresses a vulnerability that bypasses OLE mitigations in Microsoft 365 and Microsoft Office, which protect users from vulnerable COM/OLE controls." Successful exploitation of the flaw relies on an attacker sending a specially crafted Office file and convincing recipients to open it. It also noted that the Preview Pane is not an attack vector. The Windows maker said customers running Office 2021 and later will be automatically protected via a service-side change , but will b...

A critical security flaw has been disclosed in Grist‑Core , an open-source, self-hosted version of the Grist relational spreadsheet-database, that could result in remote code execution. The vulnerability, tracked as CVE-2026-24002 (CVSS score: 9.1), has been codenamed Cellbreak by Cyera Research Labs. "One malicious formula can turn a spreadsheet into a Remote Code Execution (RCE) beachhead," security researcher Vladimir Tokarev, who discovered the flaw, said . "This sandbox escape lets a formula author execute OS commands or run host‑runtime JavaScript, collapsing the boundary between 'cell logic' and host execution." Cellbreak is categorized as a case of Pyodide sandbox escape, the same kind of vulnerability that also recently impacted n8n ( CVE-2025-68668 , CVSS score: 9.9, aka N8scape). The vulnerability has been addressed in version 1.7.9, released on January 9, 2026. "A security review identified a vulnerability in the 'pyodide' ...

Cybersecurity researchers have discovered two malicious Microsoft Visual Studio Code (VS Code) extensions that are advertised as artificial intelligence (AI)-powered coding assistants, but also harbor covert functionality to siphon developer data to China-based servers. The extensions, which have 1.5 million combined installs and are still available for download from the official Visual Studio Marketplace , are listed below - ChatGPT - 中文版 (ID: whensunset.chatgpt-china) - 1,340,869 installs ChatGPT - ChatMoss（CodeMoss）(ID: zhukunpeng.chat-moss) - 151,751 installs Koi Security said the extensions are functional and work as expected, but they also capture every file being opened and every source code modification to servers located in China without users' knowledge or consent. The campaign has been codenamed MaliciousCorgi. "Both contain identical malicious code -- the same spyware infrastructure running under different publisher names," security researcher Tuval ...

Security failures rarely arrive loudly. They slip in through trusted tools, half-fixed problems, and habits people stop questioning. This week's recap shows that pattern clearly. Attackers are moving faster than defenses, mixing old tricks with new paths. "Patched" no longer means safe, and every day, software keeps becoming the entry point. What follows is a set of small but telling signals. Short updates that, together, show how quickly risk is shifting and why details can't be ignored. ⚡ Threat of the Week Improperly Patched Flaw Exploited Again in Fortinet Firewalls — Fortinet confirmed that it's working to completely plug a FortiCloud SSO authentication bypass vulnerability following reports of fresh exploitation activity on fully-patched firewalls. "We have identified a number of cases where the exploit was to a device that had been fully upgraded to the latest release at the time of the attack, which suggested a new attack path," the company said. The activi...

The U.S. Cybersecurity and Infrastructure Security Agency (CISA) on Friday added a critical security flaw affecting Broadcom VMware vCenter Server that was patched in June 2024 to its Known Exploited Vulnerabilities ( KEV ) catalog, citing evidence of active exploitation in the wild. The vulnerability in question is CVE-2024-37079 (CVSS score: 9.8), which refers to a heap overflow in the implementation of the DCE/RPC protocol that could allow a bad actor with network access to vCenter Server to achieve remote code execution by sending a specially crafted network packet. It was resolved by Broadcom in June 2024, along with CVE-2024-37080, another heap overflow in the implementation of the DCE/RPC protocol that could lead to remote code execution. Chinese cybersecurity company QiAnXin LegendSec researchers Hao Zheng and Zibo Li were credited with discovering and reporting the issues. In a presentation at the Black Hat Asia security conference in April 2025, the researchers said ...

The U.S. Cybersecurity and Infrastructure Security Agency (CISA) on Thursday added four security flaws to its Known Exploited Vulnerabilities ( KEV ) catalog, citing evidence of active exploitation in the wild. The list of vulnerabilities is as follows - CVE-2025-68645 (CVSS score: 8.8) - A PHP remote file inclusion vulnerability in Synacor Zimbra Collaboration Suite (ZCS) that could allow a remote attacker to craft requests to the "/h/rest" endpoint and allow inclusion of arbitrary files from the WebRoot directory without any authentication (Fixed in November 2025 with version 10.1.13 ) CVE-2025-34026 (CVSS score: 9.2) - An authentication bypass in the Versa Concerto SD-WAN orchestration platform that could allow an attacker to access administrative endpoints (Fixed in April 2025 with version 12.2.1 GA ) CVE-2025-31125 (CVSS score: 5.3) - An improper access control vulnerability in Vite Vitejs that could allow contents of arbitrary files to be returned to the bro...

Fortinet has officially confirmed that it's working to completely plug a FortiCloud SSO authentication bypass vulnerability following reports of fresh exploitation activity on fully-patched firewalls. "In the last 24 hours, we have identified a number of cases where the exploit was to a device that had been fully upgraded to the latest release at the time of the attack, which suggested a new attack path," Fortinet Chief Information Security Officer (CISO) Carl Windsor said in a Thursday post. The activity essentially mounts to a bypass for patches put in place by the network security vendor to address CVE-2025-59718 and CVE-2025-59719 , which could allow unauthenticated bypass of SSO login authentication via crafted SAML messages if the FortiCloud SSO feature is enabled on affected devices. The issues were originally addressed by Fortinet last month. However, earlier this week, reports emerged of renewed activity in which malicious SSO logins on FortiGate appliances...

A critical security flaw has been disclosed in the GNU InetUtils telnet daemon ( telnetd ) that went unnoticed for nearly 11 years. The vulnerability, tracked as CVE-2026-24061 , is rated 9.8 out of 10.0 on the CVSS scoring system. It affects all versions of GNU InetUtils from version 1.9.3 up to and including version 2.7. "Telnetd in GNU Inetutils through 2.7 allows remote authentication bypass via a '-f root' value for the USER environment variable," according to a description of the flaw in the NIST National Vulnerability Database (NVD). In a post on the oss-security mailing list, GNU contributor Simon Josefsson said the vulnerability can be exploited to gain root access to a target system - The telnetd server invokes /usr/bin/login (normally running as root) passing the value of the USER environment variable received from the client as the last parameter. If the client supply [sic] a carefully crafted USER environment value being the string "-f root...

Most of this week's threats didn't rely on new tricks. They relied on familiar systems behaving exactly as designed, just in the wrong hands. Ordinary files, routine services, and trusted workflows were enough to open doors without forcing them. What stands out is how little friction attackers now need. Some activity focused on quiet reach and coverage, others on timing and reuse. The emphasis wasn't speed or spectacle, but control gained through scale, patience, and misplaced trust. The stories below trace where that trust bent, not how it broke. Each item is a small signal of a larger shift, best seen when viewed together. Spear-phishing delivers custom backdoor Operation Nomad Leopard Targets Afghanistan Government entities in Afghanistan have been at the receiving end of a spear-phishing campaign dubbed Operation Nomad Leopard that employs bogus administrative documents as decoys to distribute a backdoor named FALSECUB by means o...

A new security flaw in SmarterTools SmarterMail email software has come under active exploitation in the wild, two days after the release of a patch. The vulnerability, which currently does not have a CVE identifier, is tracked by watchTowr Labs as WT-2026-0001 . It was patched by SmarterTools on January 15, 2026, with Build 9511 , following responsible disclosure by the exposure management platform on January 8, 2026. It has been described as an authentication bypass flaw that could allow any user to reset the SmarterMail system administrator password by means of a specially crafted HTTP request to the "/api/v1/auth/force-reset-password" endpoint. "The kicker of course being that said user is able to use RCE-as-a-feature functions to directly execute OS [operating system] commands," watchTowr Labs researchers Piotr Bazydlo and Sina Kheirkhah said. The problem is rooted in the function "SmarterMail.Web.Api.AuthenticationController.ForceResetPassword,"...

Cybersecurity company Arctic Wolf has warned of a "new cluster of automated malicious activity" that involves unauthorized firewall configuration changes on Fortinet FortiGate devices. The activity, it said, commenced on January 15, 2026, adding it shares similarities with a December 2025 campaign in which malicious SSO logins on FortiGate appliances were recorded against the admin account from different hosting providers by exploiting CVE-2025-59718 and CVE-2025-59719. Both vulnerabilities allow for unauthenticated bypass of SSO login authentication via crafted SAML messages when the FortiCloud single sign-on (SSO) feature is enabled on affected Devices. The shortcomings impact FortiOS, FortiWeb, FortiProxy, and FortiSwitchManager. "This activity involved the creation of generic accounts intended for persistence, configuration changes granting VPN access to those accounts, as well as exfiltration of firewall configurations," Arctic Wolf said of the developin...

Cisco has released fresh patches to address what it described as a "critical" security vulnerability impacting multiple Unified Communications (CM) products and Webex Calling Dedicated Instance that it has been actively exploited as a zero-day in the wild. The vulnerability, CVE-2026-20045 (CVSS score: 8.2), could permit an unauthenticated remote attacker to execute arbitrary commands on the underlying operating system of a susceptible device. "This vulnerability is due to improper validation of user-supplied input in HTTP requests," Cisco said in an advisory. "An attacker could exploit this vulnerability by sending a sequence of crafted HTTP requests to the web-based management interface of an affected device. A successful exploit could allow the attacker to obtain user-level access to the underlying operating system and then elevate privileges to root." The critical rating for the flaw is due to the fact that its exploitation could allow for privil...

Zoom and GitLab have released security updates to resolve a number of security vulnerabilities that could result in denial-of-service (DoS) and remote code execution. The most severe of the lot is a critical security flaw impacting Zoom Node Multimedia Routers (MMRs) that could permit a meeting participant to conduct remote code execution attacks. The vulnerability, tracked as CVE-2026-22844 and discovered internally by its Offensive Security team, carries a CVSS score of 9.9 out of 10.0. "A command injection vulnerability in Zoom Node Multimedia Routers (MMRs) before version 5.2.1716.0 may allow a meeting participant to conduct remote code execution of the MMR via network access," the company noted in a Tuesday alert. Zoom is recommending that customers using Zoom Node Meetings, Hybrid, or Meeting Connector deployments update to the latest available MMR version to safeguard against any potential threat. There is no evidence that the security flaw has been exploited ...

Security vulnerabilities were uncovered in the popular open-source artificial intelligence (AI) framework Chainlit that could allow attackers to steal sensitive data, which may allow for lateral movement within a susceptible organization. Zafran Security said the high-severity flaws, collectively dubbed ChainLeak , could be abused to leak cloud environment API keys and steal sensitive files, or perform server-side request forgery (SSRF) attacks against servers hosting AI applications. Chainlit is a framework for creating conversational chatbots. According to statistics shared by the Python Software Foundation, the package has been downloaded over 220,000 times over the past week. It has attracted a total of 7.3 million downloads to date. Details of the two vulnerabilities are as follows - CVE-2026-22218 (CVSS score: 7.1) - An arbitrary file read vulnerability in the "/project/element" update flow that allows an authenticated attacker to access the contents of any ...

A security vulnerability has been disclosed in the popular binary-parser npm library that, if successfully exploited, could result in the execution of arbitrary JavaScript. The vulnerability, tracked as CVE-2026-1245 (CVSS score: 6.5), affects all versions of the module prior to version 2.3.0 , which addresses the issue. Patches for the flaw were released on November 26, 2025. Binary-parser is a widely used parser builder for JavaScript that allows developers to parse binary data. It supports a wide range of common data types, including integers, floating-point values, strings, and arrays. The package attracts approximately 13,000 downloads on a weekly basis. According to an advisory released by the CERT Coordination Center (CERT/CC), the vulnerability has to do with a lack of sanitization of user-supplied values, such as parser field names and encoding parameters, when the JavaScript parser code is dynamically generated at runtime using the "Function" constructor. ...