linux | Breaking Cybersecurity News | The Hacker News

Attackers can log in to accounts that have no password, such as SSH key-only accounts, on some Alpine Linux servers running the standard openssh-server package. They need network access to the server, an account name, and a password between 257 and 1,024 bytes long. OpenSSH, which rates the flaw critical, released version 10.6p2 today to block it. Alpine has published fixed packages for every release back to 3.16. The attack works when the OpenSSH server (sshd) checks passwords without the Pluggable Authentication Module (PAM) interface, password logins are enabled, and at least one other account on the machine has a password. Alpine's openssh-server package is built without PAM, and password logins are on by default. The flaw comes from how sshd works with musl, the C library that Alpine is built on. Non-Linux systems, Linux systems built on glibc, and systems that check passwords through PAM are not affected, said Damien Miller of the OpenSSH project. He told anyone run...

OpenAI on Wednesday detailed a pipeline that employed an upcoming cyber-focused artificial intelligence (AI) model to validate and patch 948 local privilege escalation vulnerabilities in Linux for $1.2 million in API costs. "Our prototype identified and analyzed 2,308 candidate Linux kernel findings, dynamically reproduced 1,724 vulnerabilities, and produced 948 local privilege escalation (LPE) exploits that could allow an unprivileged local user to gain root access," the AI company said . The findings build upon 24 LPE exploits that OpenAI revealed were discovered by its GPT‑5.5‑Cyber model back in June 2026. The latest research turns this process into an agentic pipeline comprising five stages - Vulnerability discovery, where agents identify high-value audit targets (i.e., parts of the codebase that are security-relevant and reachable by low-privileged users) and look for candidate findings Dynamic validation, where agents attempt to reproduce each candidate ...

A flaw in APT , the package manager for Debian and Ubuntu, allows an attacker who can modify package downloads to swap a checked package for their own. The attacker's code then runs as root, according to advisories that  Debian ,  Ubuntu , and  APT's developers  published on November 4. The attack needs APT to retry failed downloads, which it does by default from Debian 12 and Ubuntu 22.04 onward. Debian has released fixed versions of APT for the flaw, CVE-2026-109518 . APT's developers, who call the flaw critical, say updates for Ubuntu and its Ubuntu Pro subscription service are being released. Ubuntu 14.04 users with Ubuntu Pro can already get one. Older releases, such as Debian 11 and Ubuntu 20.04, are not exposed by default, according to Ubuntu. But many user scripts may have turned on the retry setting, Acquire::Retries, on those releases anyway, APT's developers say. Debian's testing branch was still on the  vulnerable version 3.3.5  at...

Two flaws in the Xen hypervisor allow a malicious guest virtual machine (VM) to read and write the memory of other VMs on the same host, including dom0. Dom0 is the VM that, by default, has full permissions and manages the others. Patches are out, and there is no known mitigation, the Xen Project said in an  advisory  on November 3. All Xen versions from 4.6 onward are vulnerable, while 4.5 and earlier are not. The flaws are tracked as CVE-2026-102703 and CVE-2026-102704 , under Xen advisory XSA-523. The Xen Project credited AI company Anthropic with finding the flaws using its Claude model. Stephan Lipp of Ada Logics then validated the finding, and the CodeAnt AI Security Research Team later independently reported the same issue. The flaws are in grant copy, the operation Xen uses to copy data between VMs. Each VM tells Xen which of its memory pages other VMs may use, and Xen checks those permissions. To save time on a batch of copies within the same memory page, ...

An attacker broke into the update system of the cPGuard security tool on November 2 and used it to send a malicious script to customers' Linux servers. The script installed a backdoor and collected password hashes and other sensitive files from servers that ran it, cPGuard maker OPSSHIELD said in an advisory . In a later disclosure , OPSSHIELD said about 2,950 customer servers ran the script, which sent the files it collected back to the attacker. OPSSHIELD first named cPGuard 5.88.25 as the fix. Its later disclosure says version 5.88.26 removes the backdoor, and a follow-up update removes a scheduled task the script also left. Admins should install the latest version and then check that those files are gone. Credentials the script copied may still work after the update, so any server that may have run the script also needs new passwords and keys. At 02:06 UTC, the attacker, who has not been identified, used compromised credentials to get into cPGuard's update system. ...

Fixed kernels for a use-after-free vulnerability in the Linux kernel's IPv4 TCP code are now available for Red Hat Enterprise Linux 8, 9, and 10, while Ubuntu's fixes for its three newest long-term-support releases remain in its opt-in testing channel with no date for a regular update. The flaw, tracked as CVE-2026-98432 , can be reached by a remote, unauthenticated attacker and can lead to remote code execution,  Red Hat  and  Canonical  said. The Linux kernel's own CVE team rates the flaw 9.8 out of 10 on the CVSS scale. Red Hat, which initially rated it Moderate at 5.9, has raised its score to 9.8 and now calls it Critical. The bug has been present since Linux 4.4, and the upstream fix landed in October. What the Flaw Is When a server accepts an IPv4 TCP connection, the kernel passes IP options from the incoming request to the new socket without copying them. If the client retransmits its connection request while another processor still rea...

Cybersecurity researchers have disclosed details of a cyber espionage campaign specifically targeting Linux infrastructure associated with government entities and state-affiliated infrastructure. The activity, observed by Palo Alto Networks Unit 42 between October 2025 and April 2026, has been tracked under the moniker CL-UNK-1211 , where "CL" refers to cluster and "UNK" stands for unknown motivation. A notable aspect of the campaign concerns the use of large language models (LLMs) and/or automated artificial intelligence (AI) agents to generate payloads and execute malicious code. "The attackers behind this cluster of activity focused on Linux environments to conduct extensive reconnaissance and maintain persistent network access to support intelligence-gathering," researchers Roey Porat and Tom Fakterman said . "The attackers attempted to dump sensitive databases and exfiltrate government mailboxes to access social media accounts." T...

A critical flaw in Canonical's LXD and MicroCloud let an attacker log in as a trusted client without holding that client's private key. To do it, the attacker had to reach their HTTPS API over the network and have the trusted client's public certificate. Once in, the attacker would act as that client, with access to the cluster and its virtual machines. If the impersonated account is privileged, the attacker could gain "root access to the host machine," Canonical said. The flaw, tracked as  CVE-2026-112816 , carries a maximum CVSS score of 10.0, and Canonical has  released fixed versions  of both products. How the Flaw Works LXD and MicroCloud let remote clients access their APIs over mutual TLS, a setup in which the client presents a certificate to prove who it is. A client is trusted when its certificate is in the server's trust store, the list of identities the server will accept. The flaw was in how the server checked that certificate. It compa...

The U.S. Cybersecurity and Infrastructure Security Agency (CISA) on Thursday added two security flaws impacting Cisco and GitLab software to its Known Exploited Vulnerabilities ( KEV ), citing evidence of active exploitation. The vulnerabilities are listed below - CVE-2026-97229 (CVSS score: 10.0) - An integer overflow or wraparound vulnerability in GitLab Community Edition and Enterprise Edition that could allow an unauthenticated user to execute arbitrary code on the GitLab server via a specially crafted regular expression in a CI/CD configuration due to insufficient regular expression validation. CVE-2026-76418 (CVSS score: 8.6) - An unchecked return value to NULL pointer dereference vulnerability in Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Secure Firewall Threat Defense (FTD) Software that could allow an unauthenticated, remote attacker to cause the device to reload unexpectedly, resulting in a denial-of-service (DoS) condition. The devel...

A flaw in the Linux kernel's TCP code, tracked as  CVE-2026-98432 , affects Ubuntu, Red Hat Enterprise Linux (RHEL), and other Linux distributions. The kernel's own CVE team rates it 9.8 out of 10 on the CVSS scale. Anthropic said  on October 27 that its AI model wrote an exploit that uses the flaw to let a remote attacker with no credentials run commands as root on Linux servers with a multipath TCP listener. As of October 29, Ubuntu and RHEL have not released a fixed kernel. Red Hat, Amazon, Oracle, and SUSE score the flaw between 5.9 and 8.1, lower than the kernel team's 9.8. The flaw is a race condition in the code that sets up new IPv4 TCP connections. It can make the kernel read memory it has already freed, a bug type known as a use-after-free. The kernel fix  credits Anthropic researcher Xinyang Ge with reporting the bug. Neither the CVE record nor the fix mentions multipath TCP (MPTCP). The link between that feature and this bug comes from Anthropic'...

An attacker tried to exploit a critical GitLab vulnerability on the Alpine Linux project's own GitLab server a week after GitLab  released a fix , Alpine Linux  said  on 28 October. The flaw, CVE-2026-97229 (CVSS score: 10.0), can let an attacker run code on a GitLab server through a crafted regular expression in a CI configuration. Alpine found no evidence that the attack worked but cannot rule it out, so it rebuilt the server from scratch and reset every account's password. GitLab's fix  is a set of patches to the Ruby that GitLab ships in its own packages and container images. Alpine's GitLab image used standard Ruby, so upgrading the server to GitLab 19.3.6 on 22 October did not fix the flaw. For anyone running GitLab on their own Ruby, built from source or in their own container image, "upgrading GitLab is not enough," Alpine said. Those servers also need  Ruby 3.3.13, 3.4.12, 4.0.9 or later , and users of Alpine's alpinelinux/gitlab image...

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...