linux | Breaking Cybersecurity News | The Hacker News

Cybersecurity researchers have disclosed details of what appears to be an artificial intelligence (AI)-assisted attack orchestrated by a suspected China-nexus threat actor that has leveraged the PHP2Shell vulnerabilities to breach exposed systems. The activity, which was observed on October 25, 2026, involved an attacker combining PHP2Shell with a kernel privilege escalation exploit to root 25 servers, including three systems in a U.S. government-affiliated environment. "The affected devices run specific versions of a large vendor's firewall software," cybersecurity firm Dream said . "The attacker then launched attacks against Active Directory. The recovered artifacts confirm credential extraction and directory enumeration." The name of the affected vendor was not disclosed, but the Israeli company said it notified the entity. The attack chain essentially brings together two sets of vulnerabilities impacting PHP and the Linux kernel - PHP2Shell , ...

A critical 16-year-old flaw in EDK II , the open-source code that most hardware makers use to build UEFI firmware, can allow an attacker to run code on a machine before its operating system loads, but only while the machine is booting over the network. UEFI firmware is the software that runs first when a computer is switched on, before the operating system. An attacker who can reach the machine with a crafted network message during such a network boot can hang the boot, or, with work tailored to the exact firmware build, run their own code before Secure Boot and other startup defenses load. An attacker needs no password and no existing access to the machine, but does need to reach it over the network during the short window when it is booting this way. Red Hat and SUSE, which both ship the affected code, rated the flaw as one an attacker exploits from an adjacent network position rather than across the open internet. TianoCore, the project behind EDK II,  published an advi...

Adobe has released patches to address multiple critical security flaws in Campaign Classic that, if successfully exploited, could result in arbitrary code execution, security feature bypass, and privilege escalation. The list of eight vulnerabilities is as follows - CVE-2026-104351 (CVSS score: 9.9) - A code injection vulnerability that could lead to arbitrary code execution. CVE-2026-104353 (CVSS score: 9.9) - An operating system code injection vulnerability that could lead to arbitrary code execution. CVE-2026-105780 (CVSS score: 9.9) - An incorrect authorization vulnerability that could lead to arbitrary code execution. CVE-2026-105489 (CVSS score: 9.9) - An SQL injection vulnerability that could lead to security feature bypass. CVE-2026-105781 (CVSS score: 9.8) - An SQL injection vulnerability that could lead to security feature bypass. CVE-2026-104350 (CVSS score: 9.3) - A reflected cross-site scripting vulnerability that could lead to privilege escalation....

Tailscale has released  version 1.104.4  to fix flaws in its built-in SSH server that could let an attacker reach services and files on other servers that only the root user should be able to touch. The flaws are in how Tailscale SSH forwards network connections, a job the Tailscale background process carries out with root privileges. To use them, an attacker must already control a device that the network's access rules permit to open an SSH session to the target, with forwarding allowed in that rule. The flaws come from a report called  Tailworm , published days before the fix by Erica Windisch of Cyberdione Labs, who tested released versions of the Tailscale client and the self-hosted headscale control server in a lab. Tailscale SSH decides who can connect using a device's identity and the network's policy file, not a password or key, so an attacker does not need stolen credentials, only a foothold on a device the policy already trusts. The ...

Linux servers running KSMBD, the kernel's built-in SMB server, are exposed to two publicly reported remote code execution flaws rated 9.0 by  Trend Micro's Zero Day Initiative , with no fix yet in the mainline kernel. One of them, ZDI-CAN-33774, can be triggered before any network authentication. The other, ZDI-CAN-33549, requires the SMB Direct transport and an RDMA-capable network interface. ZDI-CAN-33549  is an integer underflow in KSMBD's SMB Direct path. A client can supply RDMA buffer descriptors in which the first is longer than the declared payload, causing the server's size counter to wrap and allowing a subsequent memory copy to overrun the end of an allocated buffer. It requires three things: an RDMA-capable interface (hardware or the rxe software driver), a writable KSMBD share, and a client negotiating SMB Direct. ZDI-CAN-33774  requires no authentication, exposing any server running KSMBD on port 445. The flaw is a race in how KSMBD assign...

Go 1.27.3 and Go 1.26.10, released on October 20, make Go's certificate verifier reject any certificate chain that passes through one of  eight intermediate certificate authority keys. Programs built on the new release will refuse connections to sites and services whose certificates were issued under those keys. The Go team says the keys belong to one certificate authority it has not named, and that it is blocking them because of "specific security concerns around their operation." It handled the fix on its  URGENT track , the one reserved for its most serious issues, and recommends upgrading immediately. Two days earlier, on October 17, Mozilla added six intermediate certificates issued by eMudhra's emSign Root TLS CA - G3 to  OneCRL , the list Firefox uses to block certificates. The Mozilla bug behind those entries is  closed to the public , and neither Mozilla nor Go has said what prompted its action. Whether Chrome, Apple, or Microsoft have taken simil...

A newly disclosed critical flaw in the Linux kernel allows code inside a virtual machine to read memory on the host computer it runs on. A researcher demonstrated the leak against Vercel's live cloud sandboxes, and Vercel confirmed it. The flaw, now tracked as CVE-2026-99999 and nicknamed PwnEscape , is in the Linux kernel's networking code, not in any one cloud's setup, so it reaches the shared layer that cloud providers use to keep customers' workloads apart. It was found in a Vercel security challenge and reported privately before any public release, and there is no sign it has been used in a real attack. What the Researcher Showed Paulos Yibelo of the security firm pwn.ai found that specially made network packets sent from inside a virtual machine could do three things, he explained in a  technical write-up : read the host's memory, crash the host, and run code on it. All three come from the same kernel flaw. Vercel said in its  report on the challen...

A flaw in Linux's vhost subsystem lets a local user read and write kernel memory at will and become root across nearly a decade of kernel versions. In one virtualization setup, it lets an untrusted virtual machine write to the host's memory and hijack the program that runs the virtual machine. The bug is tracked as  CVE-2026-74580  and named Vghost . Tencent Zhuque Lab, which found the flaw, released a fix on August 3 and published a full write-up on October 12 with working demos of both attacks. There is no public sign it has been exploited yet. vhost is the part of the Linux kernel that speeds up network and other input/output for virtual machines and containers. A local user reaches it by opening a device node, usually /dev/vhost-net or /dev/vhost-vsock. On the host, the flaw gives an unprivileged user a reliable way to read and write any kernel address, bypass KASLR, and escalate to root. The attack is deterministic: it needs no memory grooming and ...

Security researchers have  published a full working exploit  for a pre-authentication remote code execution flaw in AnyDesk Linux that gives attackers root access before anyone approves the connection. AnyDesk patched the flaw in version 8.0.3 in June, but its  changelog  described the fix only as "fixed a bug that could lead to a crash," with no CVE assigned and no security advisory. The exploit, called AnyPwn, targets a heap buffer overflow in AnyDesk's session protocol, a remote desktop tool. The code was released on GitHub on October 8. Administrators should update AnyDesk Linux to at least version 8.0.3. The latest release is 8.1.0. What the Exploit Demonstrates The published exploit works only over direct TCP connections on port 7070. The exploit is probabilistic: the heap layout must place a target object adjacent to the overflowed buffer; otherwise, the service crashes instead of executing the attacker's command. The offsets in the published code...

Linux backdoors targeting telecom and network appliances in South Korea and Taiwan have been disguising their traffic as email services and seemingly legitimate processes to blend in and evade detection. Threat actors are known to name their malicious software after a legitimate operating system component or a process as a defense evasion measure. By borrowing the name of a real binary, it may make it appear less conspicuous among other Windows processes, lend it a false sense of trust, or be overlooked by an analyst during casual inspection. However, the backdoors examined by Rapid7 have been found to go beyond imitating file names by assuming the identities of email security products like SpamSniper and ShareTech that are widely used in enterprise environments in South Korea and Taiwan. According to vendor Jiran Group, SpamSniper is advertised as "Korea's leading email security solution" that defends organizations against spam, malware, and server attacks. T...

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...

A use-after-free in the Linux kernel's AF_UNIX socket subsystem can be used to escape a container and gain root on the host, security firm DepthFirst  said in research published September 22. The flaw, tracked as  CVE-2026-80521  (CVSS score: 7.8), was fixed upstream on August 6, but Ubuntu has not shipped the patch for its 26.04, 24.04, or 22.04 LTS releases. DepthFirst  released exploit code  targeting Ubuntu 26.04. Ubuntu's security tracker  lists the Linux package on 26.04 as "vulnerable, work in progress." The 24.04 and 22.04 releases are also affected through newer kernel packages, including those for AWS, Azure, and GCP workloads. No fix has shipped on any affected release. The flaw is not in CISA's Known Exploited Vulnerabilities catalog, and there are no confirmed reports of attacks using it. The vulnerability sits in the kernel's garbage collector for AF_UNIX sockets. That collector cleans up file descriptors passed between processes t...

A new flaw in the Linux kernel's KVM virtualization code for ARM64 processors can leave a freed piece of host memory exposed to a guest virtual machine on hosts with nested virtualization enabled. The bug, tracked as  CVE-2026-89775 , allows a guest to read and write host kernel memory, and the researcher who found it says it can be used to escape the guest and run code on the host machine. The affected code is part of the mainline Linux kernel for ARM64, and it is fixed in Linux 6.18.51, 7.2.5, and 7.3-rc1. Nested virtualization allows a guest to run its own hypervisor, enabling it to host virtual machines. On ARM64, it is off by default. It is  an experimental boot-time mode  that needs Armv8.4 hardware with a feature called FEAT_NV2, so a plain ARM64 KVM host that never turns it on is outside the reported attack path. The flaw sits in the part of KVM that handles nested virtualization on ARM64. When a guest arranges its memory in a certain way, a size calculat...

The U.S. Cybersecurity and Infrastructure Security Agency (CISA) on Friday added three security flaws impacting the Linux kernel to its Known Exploited Vulnerabilities ( KEV ) catalog, citing evidence of active exploitation. The vulnerabilities are listed below - CVE-2025-39682 (CVSS score: 9.8) - An improper check for unusual or exceptional conditions vulnerability in the TLS receive path that could allow local authenticated users to trigger memory disclosure or denial-of-service (DoS). CVE-2026-53266 (CVSS score: 8.8) - An out-of-bounds write vulnerability in the ebtables Source Network Address Translation (SNAT) Address Resolution Protocol (ARP) rewrite path that could allow a local attacker to trigger unintended system behavior, DoS, or local privilege escalation. CVE-2025-39964 (CVSS score: 7.8) - A race condition vulnerability that could allow concurrent writes to the same AF_ALG socket, allowing a local attacker to crash the system or corrupt cryptographic op...

A security researcher has released working exploit code for four Linux kernel flaws that each let a local user gain root, the highest level of access on a machine. Kernel maintainers have fixed all four over the past few weeks, so a system running an up-to-date kernel is not affected. But the exploit code is now public, and any machine still running an older kernel should be updated. The flaws are called DirtyAH6 , TUNderflow , PPPoEject , and DiagSpill . Researcher Asim Manizada found them and reported them to the Linux kernel security team in mid-July. He published a technical  write-up  with working exploits on September 18, after a coordinated hold with Linux distributions so the fixes could be released first. So far, there are no reports of the four being used in real-world attacks. The exploits are Manizada's own, are tuned to specific kernel builds, and can crash a machine, so they are meant for isolated test systems. Still, public exploit code raises the ris...

The Pakistan-aligned threat group tracked as Transparent Tribe (aka APT36 and Earth Karkaddan) has been attributed to a fresh set of cyber attacks targeting government and defense entities in India and Afghanistan. The attacks, per Zscaler ThreatLabz, involve the use of previously undocumented tools called RUSTYSHADE, RUSTYMOVE, PSNATCH, and BASHNATCH. The activity has been codenamed Operation RapidRust . "APT36 has maintained a high operational tempo and updated their tactics, techniques, and procedures (TTPs) in continued attacks targeting government and defense organizations in India and Afghanistan," Sudeep Singh , senior manager of APT Research at Zscaler ThreatLabz, said in a technical report published this week. The discovery comes a little over a month after  Acronis Threat Research Unit (TRU) tied the long-running persistent threat group to another campaign aimed at Afghan telecom providers and South Asian critical infrastructure organizations using a backdo...

Enterprises in Russia have emerged as the target of three threat activity clusters tracked as NightEagle , Hacking Cat , and Toy Ghouls , according to multiple reports from Kaspersky. The cybersecurity vendor said it has identified attacks mounted by NightEagle (aka APT-Q-95), a threat actor known to be active since at least 2023, that involve new techniques for persistence and lateral movement. "In most incidents, the attackers used compromised valid credentials to gain access to corporate VPNs," Kaspersky said in an analysis published today. "VPN connections originated from IP addresses in the Russian segment linked to Cloudflare WARP tunnels, as well as from IP addresses associated with European virtual infrastructure providers." The attacks, as highlighted in July 2025, involve the deployment of GhostContainer , a known modular backdoor that grants the operators complete access to a victim's Microsoft Exchange Server, as well as run arbitrary code, ...

Acronis has warned that a high-severity security flaw in its Backup plugin for cPanel and Web Host Manager (WHM) deployments has been exploited in the wild. The vulnerability, tracked as CVE-2026-87886 (CVSS score: 7.8), is described as a case of local privilege escalation due to insecure file permissions. It affects the following versions - Acronis Backup plugin for cPanel & WHM (Linux) before build 1.9.3.1021 - Fixed in 1.9.3 HF3 Acronis Backup extension for Plesk (Linux) before build 1.8.11.638 Successful exploitation of the flaw could allow an attacker with low privileges to escalate their permissions on a susceptible Linux version, potentially enabling them to perform unauthorized actions or run arbitrary code that could impact the confidentiality and integrity of the application. "This update contains fixes for 1 high-severity security vulnerability and should be installed immediately by all users," Acronis noted in a separate advisory for 1.9.3 HF3...

Cybersecurity researchers have disclosed details of a multi-platform campaign that uses the Message Queueing Telemetry Transport ( MQTT ) protocol as a communication channel to control Windows and Linux systems. The emerging malware family, codenamed BambooToken , is assessed to be active since at least February 2023 and put to use in attacks targeting organizations across Asia and South America. Activity linked to the malware has been detected as recently as July 2026. Lumen Black Lotus Labs said it discovered the previously undocumented malware on VirusTotal in early 2026, with evidence pointing to a skilled threat actor that has managed to stay undetected until now. The initial access vector used to deliver BambooToken remains undetermined. "The actor used Tendyron's 'OnKey' software to sideload agents into targeted machines," Black Lotus Labs said in a report shared with The Hacker News. "Tendyron creates hardware-based tokens employed in high-se...

A suspected Chinese threat actor tracked as Red Heron has been attributed to the rapid exploitation of a recently disclosed security vulnerability in Gitea to compromise internet-facing instances as part of a multi-national campaign. "Red Heron scanned 1,386 Gitea instances across seven countries and maintained a separate dataset of 477 Taiwan-based systems," Acronis Threat Research Unit (TRU) said in an analysis. "The activity progressed from source-code theft to persistent access, credential collection, and lateral movement, including root-level access to a three-node Proxmox cluster." The activity is said to have resulted in confirmed compromises affected organizations in Canada (2), Argentina (1), Taiwan (4), the U.S. (4), Qatar (1), and Sri Lanka (1), with the threat actor using Simplified Chinese labels to classify targets spanning defense, election, energy, aerospace, telecommunications, government, public safety, and research sectors. The Singapore ...