Atlassian, Apple warn customers of zero

Atlassian Confluence Data Center and Server contain a broken access control flaw (CWE-20) in publicly accessible instances that allows unauthenticated remote attackers to create unauthorized Confluence administrator accounts and gain access to the instance; the associated public PoC is titled 'Atlassian Confluence Unauthenticated Remote Code Execution'. The flaw is triggered over the network (CVSS 3.1 9.8, AV:N/AC:L/PR:N/UI:N) against any self-managed Confluence instance reachable from the internet, with no privileges or user interaction required. Attackers who exploit it gain administrator-level control of the Confluence instance, and the public PoC demonstrates this extends to unauthenticated code execution. Only self-managed Confluence Data Center and Server deployments are affected; Atlassian Cloud sites hosted on atlassian.net domains are not vulnerable. Exploitation is confirmed in the wild: CISA added it to the KEV on 2023-10-05 with known ransomware use, EPSS is 99.2%, Atlassian reported a handful of customers were already exploited, and Microsoft warned of nation-state (China-linked) abuse.

Do: Patch all internet-facing Confluence Data Center and Server instances to a fixed release per Atlassian's advisory (specific fixed versions are not listed in this data), or restrict public access/discontinue use per CISA's required action. Audit every affected instance for evidence of compromise, especially unauthorized administrator accounts created through this flaw, and report positive findings to CISA. Treat this as urgent given active exploitation by both nation-state actors and ransomware groups.

CVE-2023-42824 is a privilege escalation vulnerability in the kernel of Apple's iOS and iPadOS, addressed with improved checks in iOS 16.7.1 and iPadOS 16.7.1. It is triggered locally: an attacker who can already run code on the device (for example via a malicious app or as one stage of a chained attack) exploits the flaw to elevate privileges. Successful exploitation grants kernel-level privilege, with high confidentiality, integrity, and availability impact, meaning near-full control of the affected device. Any iPhone or iPad running iOS/iPadOS versions prior to 16.7.1 is affected, and Apple reported the issue was being actively exploited against iOS versions before 16.6. The flaw was added to CISA's Known Exploited Vulnerabilities catalog on 2023-10-05 with no public PoC listed, making patching urgent.

Do: Update affected iPhones and iPads to iOS 16.7.1 / iPadOS 16.7.1 or later (any subsequent iOS release includes the fix), and verify device versions via Settings > General > Software Update. There is no indicated workaround, so prioritize patching for high-risk users (executives, admins, journalists), since local kernel elevation bugs of this kind are commonly chained with remote code execution or sandbox-escape exploits. Per CISA's required action, apply the vendor updates promptly or restrict use of unpatched devices.

CVE-2023-5217 is a heap buffer overflow (CWE-787) in the VP8 encoding path of libvpx, the open-source video codec library bundled with Google's Chromium/Chrome browser. A remote attacker can trigger the flaw by luring a user to a crafted HTML page whose web content invokes the vulnerable VP8 encoding code, corrupting the heap and potentially achieving code execution in the affected browser. Anyone running Google Chrome/Chromium — or other browsers and software that embed libvpx, as CISA notes the library's use is 'not limited to Google Chrome' — is affected. Exploitation is confirmed: CISA added the flaw to the Known Exploited Vulnerabilities catalog on 2023-10-02 (ransomware association: unknown), though no public proof-of-concept is available and a CVSS score has not been published; EPSS puts the 30-day exploitation probability at 49% (99th percentile). Defenders should treat this as an actively exploited browser vulnerability requiring prompt patching.

Do: Update Chrome/Chromium to the vendor release that fixes CVE-2023-5217 — Google shipped the fix with its late-September 2023 stable-channel security update, so verify the exact build number in Google's advisory (it is not specified in the source data). Also patch any other products bundling libvpx (other browsers, media/ffmpeg-based tooling) per vendor instructions, and ensure KEV compliance by applying the required mitigations or discontinuing use of affected builds by the CISA deadline.