The read_scalar and read_scalar_at functions are unsound because they allow transmuting values without unsafe blocks.

The following example shows how to create a dangling reference:

fn main() {
    #[derive(Copy, Clone, PartialEq, Debug)]
    struct S(&'static str);
    impl flatbuffers::EndianScalar for S {
        fn to_little_endian(self) -> Self { self }
        fn from_little_endian(self) -> Self { self }
    }
    println!("{:?}", flatbuffers::read_scalar::<S>(&[1; std::mem::size_of::<S>()]));
}

Anyone who uses total_size(..) function to partial read the length of any FixVec will get an incorrect result, due to an incorrect implementation. This has been resolved in the 0.7.2 release.

Code generated by flatbuffers' compiler is unsafe but not marked as such. See https://github.com/google/flatbuffers/issues/6627 for details.

For example, if generated code is used to decode malformed or untrusted input, undefined behavior (and thus security vulnerabilities) is possible even without the use of the unsafe keyword, violating the the meaning of "safe" code;

All users that use generated code by flatbuffers compiler are recommended to:

1. not expose flatbuffer generated code as part of their public APIs
2. audit their code and look for any usage of follow, push, or any method that uses them (e.g. self_follow).
3. Carefully go through the crates' documentation to understand which "safe" APIs are not intended to be used.

ring::aead::quic::HeaderProtectionKey::new_mask() may panic when overflow checking is enabled. In the QUIC protocol, an attacker can induce this panic by sending a specially-crafted packet. Even unintentionally it is likely to occur in 1 out of every 2**32 packets sent and/or received.

On 64-bit targets operations using ring::aead::{AES_128_GCM, AES_256_GCM} may panic when overflow checking is enabled, when encrypting/decrypting approximately 68,719,476,700 bytes (about 64 gigabytes) of data in a single chunk. Protocols like TLS and SSH are not affected by this because those protocols break large amounts of data into small chunks. Similarly, most applications will not attempt to encrypt/decrypt 64GB of data in one chunk.

Overflow checking is not enabled in release mode by default, but RUSTFLAGS="-C overflow-checks" or overflow-checks = true in the Cargo.toml profile can override this. Overflow checking is usually enabled by default in debug mode.