USN-4576-1 fixed a vulnerability in the overlay file system implementation in the Linux kernel. Unfortunately, that fix introduced a regression that could incorrectly deny access to overlay files in some situations. This update fixes the problem.
We apologize for the inconvenience.
Original vulnerability details:
Giuseppe Scrivano discovered that the overlay file system in the Linux kernel did not properly perform permission checks in some situations. A local attacker could possibly use this to bypass intended restrictions and gain read access to restricted files.
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