Description

An out-of-bounds write issue was addressed by removing the vulnerable code. This issue is fixed in macOS Golden Gate 27, macOS Sequoia 15.8, macOS Tahoe 26.7. Connecting to a malicious WebDAV server may lead to unexpected app termination.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "6.5",
  "pubDate": "2026-09-14T21:17:07.010Z",
  "pubdate": "2026-09-14T21:17:07.010Z",
  "executiveSummary": "This vulnerability is an out-of-bounds write issue identified within the WebDAV implementation on affected macOS platforms. The flaw is triggered when a client establishes a connection to a maliciously crafted WebDAV server.\nThe vulnerability allows an attacker to induce an out-of-bounds write condition, resulting in unexpected application termination or potential instability. The impact is primarily categorized as a denial-of-service vector targeting the client-side application handling WebDAV communications.\nAffected systems include macOS Golden Gate 27, macOS Sequoia 15.8, and macOS Tahoe 26.7. There is no requirement for prior authentication; however, successful exploitation requires the victim to interact with or connect to a malicious remote server.\nRisk implications center on service disruption and potential memory corruption. Organizations should prioritize updating to the specified patched versions to remediate the vulnerable code path.",
  "technicalDetails": "The vulnerability stems from an insufficient boundary check during the processing of data packets received from a remote WebDAV server. An out-of-bounds write occurs when the application attempts to write data beyond the allocated buffer limits of a memory structure during the parsing of WebDAV protocol responses.\nAttack flow begins with the victim client initiating a connection to a server under the control of an attacker. Upon connection, the malicious server transmits specifically crafted WebDAV responses designed to bypass standard length validation mechanisms. The client-side WebDAV implementation, failing to adequately sanitize or verify the incoming data length against the destination buffer, performs a write operation that exceeds the allocated memory segment.\nThis memory corruption event disrupts the integrity of the application's process space. Depending on the memory layout and the nature of the overflow, the application encounters an invalid state, leading to an immediate crash or unexpected termination. The vulnerable code component responsible for handling the protocol handshake and subsequent data exchange was identified as failing to implement strict bounds checking during buffer write operations.\nExploitation does not require authentication from the attacker, relying instead on the victim's interaction with the malicious infrastructure. While the primary impact described is application termination, out-of-bounds write conditions are inherently dangerous as they can potentially facilitate arbitrary code execution if the memory corruption is leveraged to overwrite critical control structures or function pointers in the process's heap or stack, though this remains dependent on the specific memory management environment of the affected macOS versions.\nThe fix involved the complete removal of the vulnerable code segment, ensuring that the buffer management logic no longer permits write operations outside of defined constraints when communicating with WebDAV endpoints."
}