USN-5092-3

USN-5092-2 fixed vulnerabilities in Linux 5.11-based kernels. Unfortunately, for Linux kernels intended for use within Microsoft Azure environments, that update introduced a regression that could cause the kernel to fail to boot in large Azure instance types. This update fixes the problem.

We apologize for the inconvenience.

Original advisory details:

Valentina Palmiotti discovered that the io_uring subsystem in the Linux kernel could be coerced to free adjacent memory. A local attacker could use this to execute arbitrary code. (CVE-2021-41073)

Ofek Kirzner, Adam Morrison, Benedict Schlueter, and Piotr Krysiuk discovered that the BPF verifier in the Linux kernel missed possible mispredicted branches due to type confusion, allowing a side-channel attack. An attacker could use this to expose sensitive information. (CVE-2021-33624)

Benedict Schlueter discovered that the BPF subsystem in the Linux kernel did not properly protect against Speculative Store Bypass (SSB) side- channel attacks in some situations. A local attacker could possibly use this to expose sensitive information. (CVE-2021-34556)

Piotr Krysiuk discovered that the BPF subsystem in the Linux kernel did not properly protect against Speculative Store Bypass (SSB) side-channel attacks in some situations. A local attacker could possibly use this to expose sensitive information. (CVE-2021-35477)

It was discovered that the tracing subsystem in the Linux kernel did not properly keep track of per-cpu ring buffer state. A privileged attacker could use this to cause a denial of service. (CVE-2021-3679)

It was discovered that the Option USB High Speed Mobile device driver in the Linux kernel did not properly handle error conditions. A physically proximate attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2021-37159)

Alexey Kardashevskiy discovered that the KVM implementation for PowerPC systems in the Linux kernel did not properly validate RTAS arguments in some situations. An attacker in a guest vm could use this to cause a denial of service (host OS crash) or possibly execute arbitrary code. (CVE-2021-37576)

It was discovered that the Virtio console implementation in the Linux kernel did not properly validate input lengths in some situations. A local attacker could possibly use this to cause a denial of service (system crash). (CVE-2021-38160)

Michael Wakabayashi discovered that the NFSv4 client implementation in the Linux kernel did not properly order connection setup operations. An attacker controlling a remote NFS server could use this to cause a denial of service on the client. (CVE-2021-38199)

It was discovered that the Sun RPC implementation in the Linux kernel contained an out-of-bounds access error. A remote attacker could possibly use this to cause a denial of service (system crash). (CVE-2021-38201)

It was discovered that the MAX-3421 host USB device driver in the Linux kernel did not properly handle device removal events. A physically proximate attacker could use this to cause a denial of service (system crash). (CVE-2021-38204)

It was discovered that the Xilinx 10/100 Ethernet Lite device driver in the Linux kernel could report pointer addresses in some situations. An attacker could use this information to ease the exploitation of another vulnerability. (CVE-2021-38205)