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VU#718077: UEFI Shell module embedded in SPI Flash can be used to bypass Secure Boot

CERT/CC details VU#718077: UEFI Shell embedded in SPI flash lets attackers bypass Secure Boot and execute pre-boot code; patches issued.

CERT/CC's VU#718077, reported by Eclypsium researcher Stas Lyakhov, describes how a UEFI Shell embedded in SPI flash can be abused by attackers who can modify UEFI boot configuration, creating multiple boot entries that bypass controls preventing the Shell from launching under Secure Boot. The Shell's dmem and mm commands allow arbitrary physical memory read/write, letting attackers overwrite Secure Boot values and execute unauthorized pre-boot code that can persist across reboots and OS reinstalls while degrading EDR effectiveness. AMI confirmed its Aptio UEFI BDS module is affected (CVE-2026-33197), and Cisco published an advisory for a variation affecting UCS Servers and UCS-based appliances (CVE-2026-20293). Firmware patches are being rolled out through OEM and IBV BIOS build pipelines.

VU#728712: Konami's Metal Gear Online 3 contains a heap-based buffer overflow

CERT/CC details CVE-2026-19874, a heap overflow in Metal Gear Online 3 letting match hosts execute code on lobby members' machines.

VU#728712 describes a heap-based buffer overflow in Konami's Metal Gear Online 3, tracked as CVE-2026-19874, affecting version 1.1.2.8 (Steam AppID 287700). The input-validation flaw lies in processing Steam lobby metadata tied to the player-removal feature, letting a match host trigger remote code execution on lobby members' machines via specially crafted data. The game is an 8v8 competitive shooter using Steam Matchmaking for lobbies.

Fake CVE-2023

A fake PoC for WinRAR RCE CVE-2023-40477 posted on GitHub actually deploys VenomRAT through a multi-step infection chain targeting researchers.

Four days after Zero Day Initiative publicly disclosed the WinRAR RCE vulnerability CVE-2023-40477 on August 17, 2023, an actor using the alias whalersplonk published a fake proof-of-concept on GitHub. The Python script actually repurposed public PoC code for GeoServer SQL injection CVE-2023-25157 and triggered an infection chain ending in VenomRAT. The README and an accompanying video lured users into running the script; the video drew over 100 plays. Unit 42 assesses the actor was opportunistic, targeting other miscreants adopting new vulnerabilities rather than researchers specifically.

Palo Alto Unit 42 · Aug 17, 2026MalwareCVE-2023-40477CVE-2023-25157

USN-8767-1: Snapcast vulnerability

Ubuntu patches Snapcast mishandling of crafted JSON-RPC requests enabling remote code execution and data exposure.

Ubuntu security notice USN-8767-1 addresses a vulnerability in Snapcast, a multiroom audio streaming server. The software incorrectly handled crafted JSON-RPC requests, which could allow a remote attacker to execute arbitrary code or obtain sensitive information. Users are advised to update the snapcast package.

Ubuntu Security Notices · 1d agoAdvisory

USN-8739-2: ImageMagick vulnerabilities

Ubuntu releases USN-8739-2, extending ImageMagick fixes for four CVEs including possible arbitrary code execution to Ubuntu 24.04 LTS.

USN-8739-2 provides the ImageMagick fixes from USN-8739-1 for Ubuntu 24.04 LTS. The flaws stem from incorrect handling of certain images that could allow an attacker to cause a denial of service or possibly execute arbitrary code. The affected CVEs are CVE-2026-56366, CVE-2026-56368, CVE-2026-56371, and CVE-2026-56373.

USN-8563-5: nginx vulnerability

Ubuntu ships improved nginx fix for CVE-2026-42533 after earlier patch regression; flaw allows remote crash and possible code execution.

USN-8563-5 provides a better fix for CVE-2026-42533 after the original fix from USN-8563-1 was backed out in USN-8563-2 because it caused a regression. The flaw stems from nginx incorrectly handling certain map directives using regex matching and capture variables, allowing a remote attacker to crash nginx, causing denial of service, or possibly execute arbitrary code. The original advisory also described a use-after-free in the ngx_http_ssi_module when configured with Server-Side Includes, proxy_pass, and proxy buffering.

USN-8749-1: CivetWeb vulnerabilities

Ubuntu USN-8749-1 patches CivetWeb URI and HTTP request parsing flaws enabling remote DoS or possible code execution.

Ubuntu Security Notice USN-8749-1 addresses two CivetWeb vulnerabilities. CVE-2025-55763 involves incorrect URI parsing that could allow a remote attacker to cause denial of service or execute arbitrary code, affecting Ubuntu 22.04 LTS and 24.04 LTS. CVE-2025-9648 involves incorrect HTTP request parsing enabling remote denial of service.

USN-8739-1: ImageMagick vulnerabilities

Canonical released USN-8739-1 fixing five ImageMagick flaws that could cause denial of service or arbitrary code execution.

Ubuntu security notice USN-8739-1 patches five ImageMagick vulnerabilities: CVE-2026-56366, CVE-2026-56368, CVE-2026-56371, and CVE-2026-56373 allow denial of service via crafted images on Ubuntu 14.04 through 22.04 LTS. CVE-2026-56370 affects Ubuntu 22.04 LTS and 26.04 LTS and could allow denial of service or arbitrary code execution. Users should apply the updated ImageMagick packages to affected releases.