CVE-2025-31277: Buffer Overflow in Apple Safari and OS Platforms Enables Remote Code Execution via Malicious Web Content

CVE-2025-31277: Buffer Overflow in Apple Safari and OS Platforms Enables Remote Code Execution via Malicious Web Content

CVE ID: CVE-2025-31277 Vendor: Apple Affected Products: Safari, iOS, iPadOS, macOS, watchOS, visionOS, tvOS Vulnerability Type: Buffer Overflow / Memory Corruption CISA KEV Patch Deadline: April 3, 2026 (federal agencies)

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Vulnerability Overview

CVE-2025-31277 is a buffer overflow vulnerability affecting Apple Safari and every major Apple operating system platform, including iOS, iPadOS, macOS, watchOS, visionOS, and tvOS. The flaw resides in the processing of web content — meaning any Safari-rendered page or embedded web view can serve as the attack surface.

When a user visits a maliciously crafted website or opens a document containing crafted web content, the vulnerable component fails to properly validate input buffer boundaries. The resulting overflow corrupts adjacent memory regions, giving an attacker a primitive to redirect execution flow and achieve arbitrary code execution at the privilege level of the targeted process.

Technical Analysis

Buffer overflow vulnerabilities of this class are well-understood but consistently dangerous. The attack vector is network-accessible and requires no authentication — a user simply navigating to an attacker-controlled URL is sufficient to trigger the condition. There is no requirement for the attacker to have prior access to the device or network segment.

Memory corruption achieved through the overflow can overwrite function pointers, return addresses, or heap metadata, depending on the specific allocation layout at runtime. Successful exploitation grants arbitrary code execution with the privileges of the Safari process or the invoking application. On iOS and iPadOS, this can translate to unauthorized access to locally stored credentials, session tokens, photos, contacts, and health data. On macOS, successful exploitation can serve as a foothold for lateral movement across enterprise environments if the device is joined to organizational networks or has access to shared resources.

The flaw affects Apple's entire consumer and enterprise device ecosystem simultaneously. Safari is the default and, on iOS and iPadOS, the only permitted browser rendering engine, which eliminates any ability to mitigate exposure by switching browsers on those platforms without patching.

Real-World Impact

Organizations running unpatched Apple devices face meaningful risk. A single user browsing a compromised or attacker-operated site from a corporate iPhone, MacBook, or iPad can expose enterprise credentials, VPN configurations, email contents, and MDM enrollment certificates. The web-delivered attack vector lowers the bar for exploitation — phishing emails containing malicious links, malvertising campaigns, and compromised legitimate websites all serve as viable delivery mechanisms.

For SOC teams, the absence of user interaction beyond a browser visit makes this class of vulnerability particularly difficult to detect in real time. Initial exploitation leaves a narrow forensic window; evidence may be limited to memory corruption crashes, unexpected process spawning from Safari or WebKit-related processes, or anomalous outbound network connections from affected endpoints.

CISA has added CVE-2025-31277 to its Known Exploited Vulnerabilities (KEV) catalog and mandated that all federal civilian executive branch agencies remediate by April 3, 2026. The KEV listing indicates confirmed exploitation activity, though Apple and CISA have not publicly attributed active exploitation to a named threat actor at the time of this advisory.

Patching and Mitigation Guidance

Patch immediately. Apply the latest available updates for every affected Apple platform. Security updates addressing CVE-2025-31277 are distributed through Apple's standard software update mechanisms:

• iOS and iPadOS: Settings → General → Software Update
• macOS: System Settings → General → Software Update
• watchOS: Watch app → General → Software Update
• tvOS: Settings → System → Software Updates
• visionOS: Settings → General → Software Update
• Safari (macOS): Included in macOS updates; verify the installed Safari version matches Apple's patched release.

For enterprise environments, take these additional steps:

1. Audit device inventory. Use your MDM solution (Jamf, Microsoft Intune, Apple Business Manager) to identify all enrolled Apple devices and their current OS and Safari versions. Prioritize unpatched devices with network access to sensitive systems.

2. Enforce web content filtering. Deploy DNS-layer filtering or proxy-based controls to block known malicious domains and high-risk content categories until patches are confirmed deployed across the fleet.

3. Review endpoint telemetry. Query EDR solutions for WebKit process crashes, unusual child process creation from Safari, and unexpected outbound connections originating from browser processes on macOS endpoints. On mobile, review MDM logs for device instability or unexpected configuration changes.

4. Restrict high-risk browsing contexts. Where operationally feasible, limit Safari usage on unpatched devices to internal, trusted sites only until remediation is complete.

5. Validate patch deployment. After pushing updates via MDM, confirm compliance using device compliance policies and generate exception reports for devices that failed to update within your defined SLA.

Organizations subject to FISMA or operating under federal contracting requirements must treat the CISA KEV deadline of April 3, 2026, as a hard cutoff. Non-federal organizations should treat the KEV listing as confirmation that exploitation is occurring and act on the same timeline or faster.