A bug in the SmallVec::insert_many method caused it to allocate a buffer that was smaller than needed. It then wrote past the end of the buffer, causing a buffer overflow and memory corruption on the heap.

This bug was only triggered if the iterator passed to insert_many yielded more items than the lower bound returned from its size_hint method.

The flaw was corrected in smallvec 0.6.14 and 1.6.1, by ensuring that additional space is always reserved for each item inserted. The fix also simplified the implementation of insert_many to use less unsafe code, so it is easier to verify its correctness.

Thank you to Yechan Bae (@Qwaz) and the Rust group at Georgia Tech’s SSLab for finding and reporting this bug.

Insufficient archive range validation could allow a crafted archive to reach ArchivedString::deserialize with an invalid pointer. A reported reproducer used rkyv::from_bytes to deserialize a struct containing strings, a vector, a box, and an optional hash map. AddressSanitizer detected a heap use-after-free during string deserialization.

The flaw could be triggered through the safe checked deserialization API when processing malicious archive bytes. Version 0.8.17 rejects the malformed archive during validation. Users who process untrusted archives should upgrade to 0.8.17 or later.

The archive validator could accept certain malformed relative pointers and invalid ArchivedHashTable states. In particular, the hash table verifier did not ensure that the number of occupied buckets matched the table's declared length.

A crafted archive could pass the checks performed by the safe rkyv::access and rkyv::from_bytes APIs and then cause an out-of-bounds read in later validation, lookup, or deserialization. Depending on the input, this could perform scalar or SIMD reads outside the archive buffer or crash the process.

Version 0.8.17 strengthens archive range validation and rejects hash tables whose number of occupied buckets does not match their declared length. Users who process untrusted archives should upgrade to 0.8.17 or later.

Shared pointer validation keyed already-validated pointees by their address and type, but did not include pointer metadata. For unsized pointees, an archive could therefore contain multiple Rc, Arc, or weak pointers that shared a data address but used different metadata, such as different slice lengths.

Once the first pointer had been validated, later pointers to the same address skipped pointee validation. The safe checked rkyv::access API could consequently return a slice with a forged length, allowing safe indexing to read out of bounds. The same validation bypass was reachable through checked deserialization with rkyv::from_bytes.

Version 0.8.17 includes pointer metadata in shared pointer validation and rejects conflicting metadata. The 0.7 series is also affected but is no longer supported by upstream. Users who process untrusted archives should upgrade to 0.8.17 or later.