An integer value is specified to be shifted by a negative amount or an amount greater than or equal to the number of bits contained in the value causing an unexpected or indeterminate result.
Specifying a value to be shifted by a negative amount is undefined in various languages. Various computer architectures implement this action in different ways. The compilers and interpreters when generating code to accomplish a shift generally do not do a check for this issue.
Specifying an over-shift, a shift greater than or equal to the number of bits contained in a value to be shifted, produces a result which varies by architecture and compiler. In some languages, this action is specifically listed as producing an undefined result.
Implicitly or explicitly add checks and mitigation for negative or over-shift values.
Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)
CVE-2009-4307An unexpected large value in the ext4 filesystem causes an overshift condition resulting in a divide by zero.
CVE-2012-2100An unexpected large value in the ext4 filesystem causes an overshift condition resulting in a divide by zero - fix of CVE-2009-4307.
CVE-2020-8835An overshift in a kernel allowed out of bounds reads and writes resulting in a root takeover.
CVE-2015-1607Program is not properly handling signed bitwise left-shifts causing an overlapping memcpy memory range error.
CVE-2016-9842Compression function improperly executes a signed left shift of a negative integer.