MEDIUM4.7
GHSA-rh4w-94hh-9943
MutexGuard::map can cause a data race in safe code
Details
Affected versions of the crate had a Send/Sync implementation for MappedMutexGuard that only considered variance on T, while MappedMutexGuard dereferenced to U.
This could of led to data races in safe Rust code when a closure used in MutexGuard::map() returns U that is unrelated to T.
The issue was fixed by fixing Send and Sync implementations, and by adding a PhantomData<&'a mut U> marker to the MappedMutexGuard type to tell the compiler that the guard is over U too.
Are you affected?
Enter the version of the package you're using.
Affected packages
crates.io/futures-util
Introduced in:
0.3.2Fixed in: 0.3.7Upgrade futures-util to 0.3.7 or newer (ecosystem crates.io).