A downgrade issue in macOS allowed an application to bypass newly implemented code‑signing restrictions, potentially granting the app access to user data that is normally protected. The vulnerability is mitigated in macOS Sequoia 15.4, and the description states that an app may be able to read protected data after exploitation. While the CVSS score of 6.5 indicates moderate severity, the EPSS is below 1%, meaning that active exploitation is currently rare but not impossible.

The issue affects macOS overall, with the fix applied in macOS Sequoia 15.4. No specific sub‑versions are listed beyond the mention of Sequoia 15.4, so any earlier releases that did not include the additional code‑signing restrictions are considered vulnerable.

The CVSS score of 6.5 places the vulnerability in the medium severity range. The EPSS score of less than 1% suggests an extremely low probability of exploitation, and the vulnerability is not currently listed in the CISA KEV catalog. Inference based on the description points to a downgrade attack vector, where an attacker installs an older version of an application that does not comply with the updated signing requirements. Exploitation would allow the app to read protected user data, compromising confidentiality. The overall risk is moderate, but mitigation is recommended to prevent potential data exposure.