USN-8728-1: Linux kernel (GCP) vulnerabilities
Ubuntu issued kernel security update USN-8728-1 for GCP kernels fixing Arm TLB and AMD Zen 2 privilege escalation flaws (CVE-2025-10263, CVE-2025-54518).
Ubuntu released USN-8728-1, a security update for the Linux kernel used on Google Cloud Platform images. It fixes CVE-2025-10263, where certain Arm processors complete broadcast TLB invalidation before memory writes are globally observed, allowing local attackers to bypass memory protections or escalate privileges, and CVE-2025-54518, an AMD Zen 2 operation cache isolation flaw that can corrupt higher-privilege instructions. The notice also corrects several other kernel security issues.
Risky Bulletin: Ukraine's top prosecutor resigns amid scam call center scandal
Ukraine's top prosecutor Ruslan Kravchenko resigned after NABU arrested a deputy for taking bribes protecting scam call centers running fake investment platforms.
Ukraine's anti-corruption bureau NABU arrested Serhiy Kropyva, Deputy Head of International Cooperation at the Prosecutor General's Office, alleging officials took monthly protection fees from a network of 100-500 scam call centers luring victims into fake investment platforms, with bribes reportedly growing from $700,000 to $3.5 million per month. Prosecutor General Ruslan Kravchenko resigned on Monday, calling it a political decision, while Kropyva was fired with bail set at 120 million hryvnias ($2.7 million) and over 100 call centers shut down in the past month. The newsletter also briefly covers a cyberattack crippling more than 80 Luxembourg medical practices via payment vendor BMS Engineering, ShinyHunters' claimed theft of 200,000 Florida DMV driver records, a cyberattack on the American Meteor Society, and school closures in Springfield, Massachusetts.
HVNC Backdoor Targets LATAM Organizations with Fake Tax and DocuSign Lures
A custom HVNC backdoor is targeting Latin American financial organizations via fake DocuSign and NFe tax-document lures, giving attackers hidden persistent remote access.
ANY.RUN researchers analyzed a multi-stage phishing campaign delivering a custom HVNC backdoor to banking and financial organizations in Latin America. The chain starts with fake DocuSign and NFe tax-document pages that serve per-visitor ZIP archives, followed by an LNK dropper, an NSIS loader, and a 64-bit backdoor masquerading as Windows Update Assistant. The implant provides hidden remote desktop control, keystroke monitoring, Firefox data theft, Startup-folder persistence, and EDR-aware behavior, communicating over TCP/27015.
Cloudflare Workers Spectre Attack Leaks JWT From Co
Researchers demonstrated a remote Spectre attack leaking a JWT between co-located Cloudflare Workers at 12 bits per second, 360x the 2021 rate.
Security researchers showed a remote Spectre attack against Cloudflare Workers that leaked a JWT from a co-located Worker at up to 12 bits per second with 99.16% accuracy, 360 times the 2021 demonstration rate. The attack exploited weaknesses in DyPrIs dynamic process isolation, where long-lived Durable Object invocations could run before isolation and WebSocket-heavy I/O suppressed the branch-misprediction signal. Cloudflare deployed improved DyPrIs, the V8 Sandbox, and MPK-based in-process isolation, and found no indicators of active exploitation over three years.