An anonymous reader quotes a report from Ars Technica: Researchers have analyzed a high-severity vulnerability in Linux that's able to escalate untrusted users to root by exploiting a bug you don't often see: a single errant character inside the kernel. The vulnerability, tracked as CVE-2026-23111, is located in nf_tables, a subsystem of the Linux kernel that provides packet filtering capabilities. It's used to manage firewall rules and replaces older subsystems such as iptables, ip6tables, arptables, and ebtables. The presence of a single mis-issued exclamation point in code implementing nf_tables introduced a use-after-free, a class of vulnerability that corrupts memory by placing malicious code at memory addresses that haven't been properly freed of their previous contents. CVE-2026-23111 can be exploited by an unprivileged user or process to elevate system rights to root. The exploit works by disrupting the deletion of verdicts -- a determination within the nf_tables framework that determines if a packet matches a rule calling for a certain action to be performed. This process can use what are known as catchall elements, which act as a wildcard in the event a lookup doesn't match any other element in the set. When a verdict map is deleted from memory, catchall elements are deactivated and a chain's reference counter is decremented. When errors occur the deletion can be reversed and the counter incremented. CVE-2026-53111 allows for that process to be altered. As a result, the exploit can decrement the variable an arbitrary number of times and then delete and free the chain when some objects still point to it. Although the kernel vulnerability was fixed in February, multiple proof-of-concept exploits have since emerged, including one from FuzzingLabs in April and another from Exodus Intelligence that works on Debian and Ubuntu.

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An anonymous reader quotes a report from 404 Media: Microsoft has shut down a wave of its own repositories on GitHub, including those related to Azure and AI coding agents, as it investigates a data breach, according to research from cybersecurity researchers and a statement given to 404 Media by Microsoft. Hackers planted malware that would harvest peoples' credentials when they opened it in AI coding tools like Claude Code or Gemini CLI, according to one set of researchers. The exact contours of the breach are unclear, but researchers say Microsoft has disabled more than 70 of its own repositories, and pointed to a particular package that was previously compromised. Last week, cybersecurity website OpenSourceMalware.com, which acts as a clearing house for indicators of supply chain attacks so defenders can secure their own networks, and which also publishes its own write-ups, wrote about the mass disabling of Microsoft GitHub repositories. "GitHub disabled 73 Microsoft repositories across four of its GitHub organizations -- the entire Azure Functions org, the whole Durable Task family, and a row of AI sample apps -- in a 105-second sweep on June 5," the website wrote on Friday. Is it very unusual for any company, let alone Microsoft, to disable so many of its own repositories in one go. They include 49 related to Azure, Microsoft's cloud computing arm, and some concerning AI agents. The shutdown repositories also include ones related to durabletask, a Microsoft development tool. Researchers from StepSecurity wrote on Friday that the GitHub closures came after a malicious commit was pushed to the durabletask repository. That attack planted configuration files that would harvest peoples' credentials when they opened the repository in Claude Code, Gemini CLI, Cursor, or VS Code, StepSecurity wrote. Microsoft said in a statement: "Our priority is to protect customers and the broader ecosystem. We temporarily removed some repositories as we investigated potential malicious content. Some of these repos have been restored after review, while others may remain offline while work continues. As part of our investigation, we notified a small number of customers who may have pulled down content from the affected repositories. We will continue to investigate, and if anything further is identified that requires customer action, we will reach out directly through our established support channels."

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