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Nebula Security says a patched Firefox JIT flaw could be triggered by simply visiting a malicious webpage and was also used to compromise Tor Browser. Tracked as CVE-2026-10702 , the bug provides arbitrary code execution inside the browser's renderer process. Mozilla rated it High and fixed it in the Firefox 151.0.3 update . "No settings or additional user interaction are required," Eten Zou, CEO of Nebula Security, told The Hacker News. "Visiting a malicious webpage is enough to trigger it," Zou said every Tor Browser release that incorporated a vulnerable Firefox version was affected, though researchers have not identified the exact Tor releases. On its own, the bug runs code only inside Firefox's sandboxed content process. Nebula released public exploit material and used the flaw as the first stage of IonStack, a browser-to-kernel chain built for an ARM64 device running Android 17. The released end-to-end code targets one supported Google build, a...

A new Mirai-derived botnet called Tengu can use a compromised Linux device's hardware watchdog to trigger a reboot when defenders kill its main process. If that happens, Tengu's other persistence mechanisms get another chance to relaunch it. Nozomi Networks Labs observed the dropper reaching its honeypots through Telnet credential brute force. Tengu supports 25 distributed denial-of-service (DDoS) methods. It can also run a SOCKS5 proxy, execute shell commands, and collect system and network data. The malware can update itself and retrieve additional Executable and Linkable Format (ELF) or Android package (APK) payloads. Nozomi listed architecture-specific samples for i386, amd64, MIPS, ARM, PowerPC, and m68k. The report identifies no specific vendor or device model. It also names no operator, infection count, or real-world DDoS victims. It shows what Tengu can do, not how far it has spread. Defenders should start by removing internet exposure for Telnet and other unne...

STAR Labs has published a Linux kernel exploit that turns an ordinary local user into root on the CentOS Stream 9 build it targeted. The flaw, tracked as CVE-2026-53264 (CVSS score: 7.8), is a use-after-free race in the kernel's network traffic-control subsystem. Researcher Lee Jia Jie said artificial intelligence (AI) helped him find the bug and speed up exploit development. This is local privilege escalation, not remote code execution, so an attacker needs a foothold on the machine before any of it applies. The demonstrated exploit also requires unprivileged user namespaces, the CONFIG_NET_ACT_GACT and CONFIG_NET_CLS_FLOWER kernel options, and a kernel-specific return-oriented programming (ROP) chain containing hardcoded offsets. Those conditions narrow the immediate exposure, but full exploit source code is now public. The upstream fix landed on June 1, 2026, and has since been backported to several stable kernel branches. The Linux CNA record lists vulnerable ranges begi...

The operators of the DevMan ransomware-as-a-service (RaaS) scheme are maintaining a dedicated web platform that offers affiliates the ability to build payloads, oversee earnings, and manage various aspects related to victims. Swiss cybersecurity company PRODAFT is tracking the centrally administered RaaS operation under the name Funky Mantis . "The portal combined build generation, finance, victim chat, support, victim records, teams, and payout functions," the company said in an extensive report shared with The Hacker News. "The service integrated access brokerage or access distribution with ransomware deployment. Administrators offered country-specific 'networks,' asked whether an affiliate would use personal or program-supplied access, and imposed two-to-three-day completion windows." Various analyses show that DevMan first emerged on the scene in April 2025 as an affiliate for Qilin, DragonForce, Apos, and RansomHub, before shifting to their o...

A crafted SVG submitted to Bing's image search ran commands as NT AUTHORITY\SYSTEM on Microsoft's production image-processing workers, and as root on the Linux machines in the same fleet. XBOW's testing got the same result on workers across different hosts and network ranges, so the problem sat in Bing's image tier, not on one bad machine. Microsoft issued two critical CVEs, CVE-2026-32194 and CVE-2026-32191, and rated both 9.8 on the CVSS scale. XBOW, the autonomous offensive security startup, found both and reported them privately. Bing users have no patch or mitigation to apply: Microsoft fixed both server-side before the advisories went out in March, and the records state there is "no customer action to resolve." Neither advisory recorded exploitation or public disclosure when they went up on March 19. XBOW published the exploit mechanics on July 23, after holding them back at Microsoft's request until the remediation had landed. What outlive...

Someone installed a popular AI assistant on a rented server, switched off the setting that makes it ask permission before running risky commands, and pointed it at Thailand's Ministry of Finance, which runs the country's treasury and tax collection. The agent then worked through the ministry's network on its own, checking hosts for ways to gain root access, hunting through file systems, and crawling a folder of staff personnel records going back to 2012. The operator left the agent's own logs sitting on a web server with directory listing switched on, where threat intelligence firm Hunt.io and researcher Bob Diachenko found them, along with 585 files and 470 MB of attack tooling. The tool is Hermes , an open-source assistant from Nous Research that people install to manage their mail, run chores, and take instructions over Telegram or Slack. It is not a hacking tool, and nothing here is a flaw in it. The mode the operator used, called YOLO, is a documented feat...

Cybersecurity researchers have uncovered a sandbox escape vulnerability in Anthropic's Claude Cowork that makes it possible to break out of the confines of a Linux virtual machine (VM) within which the agent runs to read or write files anywhere on the Mac. Accomplish AI, which shared details of the vulnerability with The Hacker News ahead of publication, said about 500,000 macOS users running local Cowork sessions were affected prior to it being patched. It has been codenamed SharedRoot . "We connected a folder to a fresh Claude Cowork session, sent one short message, and watched the agent escape the sandbox," Oren Yomtov, principal security researcher at Accomplish AI, said . "From inside the VM, it reached the host Mac and read and wrote files all over it, far outside the folder we'd connected, with no permission prompt anywhere." With this level of access, the agent can access any data stored on the Mac via the user's account, including SSH ke...

RefluXFS , a Linux kernel flaw disclosed on July 22 and tracked as CVE-2026-64600 , lets an unprivileged local user overwrite root-owned files on an XFS filesystem and gain persistent root access. Qualys said default installations of Red Hat Enterprise Linux and its derivatives, Fedora Server, and Amazon Linux can meet the conditions for exploitation. The company demonstrated the race against /etc/passwd and setuid-root binaries. The overwrite lands at the block layer. It survives a reboot and leaves the target's ownership, permissions, timestamps, and setuid bit untouched, so a modified setuid-root binary still runs as root. The fix was merged on July 16, and Linux vendors have begun shipping backported kernels. The patch traces the bug to Linux 4.11 in 2017: a Fixes: tag naming commit 3c68d44a2b49 and a stable backport request marked # v4.11 . Who is exposed Exploitation requires three conditions: The system runs Linux 4.11 or later without the RefluXFS fix....

Cybersecurity researchers have disclosed details of a new local privilege escalation (LPE) vulnerability in snap-confine that an unprivileged user can trigger to obtain root access and gain complete control of a target environment. The high-severity flaw, tracked as CVE-2026-8933 (CVSS score: 7.8), impacts default installations of Ubuntu Desktop 24.04, 25.10, and 26.04. The disclosure comes as 442 security flaws in Linux have been publicized over the past three days. "The issue stems from a security hardening change that inadvertently introduced a race condition during sandbox initialization," Saeed Abbasi, head of Threat Research Unit (TRU) and director of product at Qualys, said. Snap-confine is a program used internally by snapd to construct the execution environment for snap applications. Snapd is the background service or daemon that manages snap packages on Linux systems. Snaps are nothing but a software packaging format devised by Canonical that allows an app...

Cybersecurity researchers have flagged a new software supply chain attack codenamed SleeperGem targeting the Ruby ecosystem after three malicious gems were published to RubyGems with the end goal of serving additional payloads. The rogue gems are listed below - git_credential_manager (versions 2.8.0, 2.8.1, 2.8.2, 2.8.3) - Published on July 18, 2026 Dendreo (versions 1.1.3, 1.1.4) - Published on October 14, 2017 fastlane-plugin-run_tests_firebase_testlab (version 0.3.2) - Published on February 06, 2018 "Each malicious release is a loader," StepSecurity said in an analysis. "It fetches a second stage from an attacker controlled Forgejo host, checks whether it is running in a build system and skips if it is, and on a developer machine it drops a native daemon and installs persistence." One aspect of the attack that immediately stands out is that "git_credential_manager" impersonates the official Microsoft Git Credential Manager, while t...

Eleven bytes will make an unpatched OpenSSL server set aside up to 131 KB of memory for a message that never arrives. On the glibc systems Okta tested, that memory is gone until the process restarts. OpenSSL shipped the HollowByte fix in June with no CVE, no advisory, and no changelog entry pointing at it. Okta's Red Team, which reported the denial-of-service bug and named it, published the details on Thursday. The fixed releases are OpenSSL 4.0.1, 3.6.3, 3.5.7, 3.4.6, and 3.0.21 , all dated June 9. Every release on those branches before the fixed ones has it. Nothing in a normal patch pipeline will point you at them: there is no identifier for a scanner to match and no advisory to read. The flaw is that OpenSSL took the attacker's word for it. Every TLS handshake message carries a 4-byte header, three bytes of which declare how long the body will be. Older versions grew the receive buffer to that declared size the moment the header landed, before a single byte of the body ...

Cybersecurity researchers have discovered 11 old, Microsoft-signed, Unified Extensible Firmware Interface (UEFI) applications that could be abused to bypass Secure Boot on most systems using the modern firmware standard. "An attacker exploiting one of these vulnerable applications can execute untrusted code during system boot, enabling deployment of malicious UEFI bootkits or other malware," ESET researcher Martin Smolár said in a report published today. The UEFI shim bootloaders expose any UEFI-based machine that trusts Microsoft's " Microsoft Corporation UEFI CA 2011 " third-party UEFI certificate authority (CA) certificate, irrespective of the installed operating system. The certificate is used to sign third-party boot components intended to run under Secure Boot. It expired as of June 27, 2026, and has been replaced by Microsoft UEFI CA 2023 and Microsoft Option ROM UEFI CA 2023. The shim is a lightweight, open-source UEFI bootloader that acts as an ...

A Chinese threat actor tracked as UAT-7810 is actively refining its bespoke malware to expand its Operational Relay Box (ORB) network by breaking into internet-facing networking devices. According to findings from Cisco Talos, UAT-7810 is an advanced persistent threat (APT) actor that's responsible for maintaining and proliferating LapDogs , an ORB network that first came to light in June 2025. "UAT-7810 is most likely tasked with establishing Operational Relay Box (ORB) networks that can then be leveraged by associated secondary threat actors to conduct their own malicious attacks against high value targets," researchers Jungsoo An, Asheer Malhotra, Vanja Svajcer, and Brandon White said . One such China-nexus threat actor that has leveraged the infrastructure in its own attacks is UAT-5918 , which has been linked to cyber attacks targeting critical infrastructure entities in Taiwan since at least 2023 with an aim to establish persistent access within victim envir...

Researchers at  Nebula Security  have disclosed GhostLock ( CVE-2026-43499 ), a 15-year-old Linux kernel flaw that lets any logged-in user take full root control of a machine that has not been patched. The vulnerable code has shipped by default in essentially every mainstream distribution since 2011. The flaw needs no special permission, no unusual settings, and no network access; ordinary threading calls from any local program are enough. Nebula turned it into a working root exploit that is 97% reliable in its testing and also escapes containers, and says Google awarded the team $92,337 through its  kernelCTF  bug-bounty program. No one is known to be exploiting it in the wild, but Nebula has published  working exploit code , so anyone can now run it. Patching is the priority. How the bug works The kernel has a system for keeping an urgent task from getting stuck behind a trivial one. Part of it is a cleanup step that tidies up after a task...

A use-after-free bug in Linux's KVM hypervisor can be triggered from a guest virtual machine to corrupt the shadow-page state of the host kernel that runs it. Dubbed ' Januscape ' and tracked as  CVE-2026-53359 , the flaw sits in the shadow MMU code that KVM shares across both Intel and AMD. The public proof-of-concept panics the host; the researcher claims that a separate, unreleased exploit turns the same bug into full host code execution. Security researcher  Hyunwoo Kim (@v4bel) found and reported the bug. He described Januscape as the first guest-to-host exploit triggerable on both Intel and AMD, to the best of public knowledge. The flaw went unnoticed for roughly 16 years. According to Kim, the exploit was used as a zero-day submission in  Google's kvmCTF , the controlled KVM vulnerability reward program that offers up to $250,000 for full guest-to-host escapes. How It Works To run a virtual machine, KVM keeps its own private set of page tables that mi...

Cybersecurity researchers have flagged a novel Java-based remote access trojan (RAT) called QuimaRAT that's capable of targeting Windows, Linux, and macOS environments. According to LevelBlue, the cross-platform malware is advertised under a malware-as-a-service (MaaS) model, costing anywhere between $150 for one month to $1,200 for lifetime access. Other subscription tiers include $300 for three months, $500 for six months, and $700 for twelve months. "Built around a modular architecture, the RAT supports dynamic capability expansion through encrypted plugins that can be delivered, loaded, unloaded, and updated directly from its command-and-control (C2) infrastructure," the cybersecurity company said in an analysis of the malware. The malware author also advertises a builder capable of generating multiple output formats, including JAR, EXE, APP, SH, BAT, and VBS, indicating an attempt to help prospective customers package the client tailored for different enviro...

A newly disclosed Linux kernel flaw called Bad Epoll (CVE-2026-46242) lets an ordinary user with no special access take full control of a machine as root. It affects Linux desktops, servers, and Android, and a fix is out. Bad Epoll sits in the same small stretch of kernel code where Anthropic's most powerful AI model, Mythos , recently found a different bug. The AI caught one flaw and missed this one. A researcher, Jaeyoung Chung, found it and built a working attack. How the Bug Works Epoll is a standard Linux feature that lets a program watch many files or network connections at once. Servers, network services, and web browsers all lean on it. You cannot simply switch it off. Bad Epoll is a "use-after-free" bug. Two parts of the kernel try to clean up the same internal object at the same time. One frees the memory while the other is still writing into it. That brief collision lets an attacker corrupt kernel memory, then climb from a normal account up to root...

DirtyClone is a new Linux kernel privilege escalation in the DirtyFrag family. JFrog Security Research published a working exploit walkthrough for the flaw on June 25, the first public demonstration for this variant. Tracked as  CVE-2026-43503  (CVSS 8.8), it lets a local user corrupt file-backed memory through a cloned network packet and gain root. The patch landed in mainline on May 21; if your kernel does not have it, update now. When the kernel copies a network packet internally, two helper functions drop a safety flag that marks the packet's memory as shared with a file on disk. That missing flag is the entire vulnerability. The attacker loads a privileged binary like /usr/bin/su into memory, wires those memory pages into a network packet, and forces the kernel to clone it. The cloned packet passes through an IPsec tunnel that the attacker controls, and the decryption step overwrites the binary's login checks with attacker-chosen bytes. The next time anyo...

Cybersecurity researchers have flagged two previously undocumented Windows variants of what was believed to be a Linux-only backdoor called SprySOCKS . "The Windows variants discovered are internally marked as WIN_DRV and WIN_PLUS," ESET said in a report shared with The Hacker News. "Both come with a hard-coded C&C [command-and-control] configuration and support communication over TCP, UDP, and WebSocket protocols." Like its Linux counterpart, the Windows versions support more than 30 commands to facilitate system information collection, process enumeration, service management, and file system operations. WIN_DRV has also been found to utilize kernel drivers to conceal the malware's network connections, processes, files, and registry keys. In addition, the variant enables TCP traffic diversion that allows the malware operators to send commands to the backdoor through a random TCP port on the victim's device without exposing the backdoor's act...

Instead of hiding on the laptops and servers defenders watch most closely, a China-nexus group spent close to a decade hidden inside the Linux login system itself. Sygnia, which tracks the group as Velvet Ant , says it backdoored the PAM and OpenSSH components that decide who is allowed to sign in, planting its access where ordinary cleanup could not reach it. The network it targeted had no direct internet access, so the group first staged through internet-facing systems to get there. The earliest traces go back to 2016. Instead of dropping new malware that a scanner might catch, the attacker changed the trusted login programs themselves. Nothing obvious appeared, and no exploit was needed, so the activity looked like normal administration. On many machines, the attacker replaced the main PAM login module with backdoored copies. Some let them in with a secret password; others quietly recorded real usernames and passwords as people logged in. Researchers found nine separate ver...