Ubuntu Security Notice 3655-2 - USN-3655-1 fixed vulnerabilities and added mitigations in the Linux kernel for Ubuntu 14.04 LTS. This update provides the corresponding updates for the Linux Hardware Enablement kernel from Ubuntu 14.04 LTS for Ubuntu 12.04 ESM. Jann Horn and Ken Johnson discovered that microprocessors utilizing speculative execution of a memory read may allow unauthorized memory reads via a sidechannel attack. This flaw is known as Spectre Variant 4. A local attacker could use this to expose sensitive information, including kernel memory. Various other issues were also addressed.
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Ubuntu Security Notice 3655-1 - Jann Horn and Ken Johnson discovered that microprocessors utilizing speculative execution of a memory read may allow unauthorized memory reads via a sidechannel attack. This flaw is known as Spectre Variant 4. A local attacker could use this to expose sensitive information, including kernel memory. Jan H. Schonherr discovered that the Xen subsystem did not properly handle block IO merges correctly in some situations. An attacker in a guest vm could use this to cause a denial of service or possibly gain administrative privileges in the host. Various other issues were also addressed.
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Debian Linux Security Advisory 4187-1 - Several vulnerabilities have been discovered in the Linux kernel that may lead to a privilege escalation, denial of service or information leaks.
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