In the standard library in Rust before 1.29.0, there is weak synchronization in the Arc::get_mut method. This synchronization issue can be lead to memory safety issues through race conditions.

In the standard library in Rust before 1.52.0, a double free can occur in the Vec::from_iter function if freeing the element panics.

In the standard library in Rust before 1.52.0, there is an optimization for joining strings that can cause uninitialized bytes to be exposed (or the program to crash) if the borrowed string changes after its length is checked.

In the standard library in Rust before 1.19.0, there is a synchronization problem in the MutexGuard object. MutexGuards can be used across threads with any types, allowing for memory safety issues through race conditions.

In the standard library in Rust before 1.2.0, BinaryHeap is not panic-safe. The binary heap is left in an inconsistent state when the comparison of generic elements inside sift_up or sift_down_range panics. This bug leads to a drop of zeroed memory as an arbitrary type, which can result in a memory safety violation.

In the standard library in Rust before 1.52.0, the Zip implementation has a panic safety issue. It calls __iterator_get_unchecked() more than once for the same index when the underlying iterator panics (in certain conditions). This bug could lead to a memory safety violation due to an unmet safety requirement for the TrustedRandomAccess trait.

In the standard library in Rust before 1.52.0, the Zip implementation can report an incorrect size due to an integer overflow. This bug can lead to a buffer overflow when a consumed Zip iterator is used again.

In the standard library in Rust before 1.50.0, read_to_end() does not validate the return value from Read in an unsafe context. This bug could lead to a buffer overflow.

In the standard library in Rust before 1.49.0, String::retain() function has a panic safety problem. It allows creation of a non-UTF-8 Rust string when the provided closure panics. This bug could result in a memory safety violation when other string APIs assume that UTF-8 encoding is used on the same string.

In the standard library in Rust before 1.52.0, the Zip implementation calls __iterator_get_unchecked() more than once for the same index (under certain conditions) when next_back() and next() are used together. This bug could lead to a memory safety violation due to an unmet safety requirement for the TrustedRandomAccess trait.