Apple Safari EUVD-2026-40218

The victim must actively process maliciously crafted web content using an affected version of Safari - this typically means navigating to a hostile URL or opening a crafted file that Safari renders. The CVSS UI:R metric confirms user interaction is required; passive network exposure alone is not sufficient. No authentication or special account privileges are needed on the attacker's side (PR:N). No non-default Safari configuration is required - standard out-of-the-box installations on Safari <26.5.2, iOS/iPadOS <26.5.2, and macOS Tahoe <26.5.2 are affected. Limiting factors: exploitation is blocked if the user does not visit the malicious content, if outbound web access is restricted via proxy or firewall, or if the device has already been updated to 26.5.2. The scope is unchanged (S:U), meaning the crash is contained to the Safari process and does not inherently compromise the OS or other applications.

The CVSS 3.1 score of 6.5 (Medium) is internally consistent: AV:N reflects that a hostile web page can reach any Safari user over the network, AC:L confirms no special conditions are required, PR:N indicates no credentials are needed, but UI:R correctly captures that the victim must navigate to or open the crafted content. Impact is confined to A:H (crash/denial-of-service) with C:N and I:N, ruling out data theft or tampering based on available data. This aligns with the description's 'unexpected Safari crash' outcome. No EPSS score was provided, limiting probabilistic exploitation forecasting. There is no CISA KEV listing and no POC reported, so exploitation remains theoretical at this time. Real-world priority is moderate: the attack requires user interaction and yields only a crash, not code execution - making it disruptive rather than catastrophic. However, given Safari's role as the mandatory browser engine on iOS and iPadOS, the population of potentially affected devices is very large. Organizations with high-value iOS fleets (enterprise, government) should treat this as a prompt patch, while individual risk is lower absent active exploitation evidence.

An attacker registers or compromises a website and embeds maliciously crafted HTML or media content designed to trigger a buffer boundary violation in Safari's web content renderer. A target user visits the page - via a phishing link, malvertising redirect, or social engineering - and Safari processes the content, triggering the memory handling flaw and causing the browser to crash. The attack requires no credentials and works against default Safari installations, but depends entirely on luring the victim to the hostile URL. No POC code has been identified at time of analysis.