{"id":"RUSTSEC-2026-0435","revision":"4dc4f6f9e99a44e6a90cda4b7e2e87ee","records":[{"revision":"4dc4f6f9e99a44e6a90cda4b7e2e87ee","observedAt":"2026-11-02T13:57:24.218+00:00","statement":{"source":"osv","id":"RUSTSEC-2026-0435","aliases":["BIT-thrift-2026-43868","CVE-2026-43868","GHSA-2f9f-gq7v-9h6m"],"title":"Unbounded memory allocation in `thrift` binary protocol `read_bytes`","description":"Affected versions of the `thrift` crate size a buffer directly from an attacker-controlled 4-byte length read off the wire, before reading any payload and with no upper bound, allowing a hostile peer to force a large eager allocation or an immediate abort (denial of service, CWE-400 / CWE-789). This is the Rust implementation's instance of the CVE-2020-13949 pattern, published by the Apache Thrift PMC as CVE-2026-43868.\n\n## Details\n\nIn `TBinaryInputProtocol::read_bytes` (`src/protocol/binary.rs`), the length is read as a `i32` from the transport and cast straight to `usize` to size a zeroing buffer **before** any payload is read:\n\n```rust\nfn read_bytes(&mut self) -> crate::Result<Vec<u8>> {\n    let num_bytes = self.transport.read_i32::<BigEndian>()? as usize; // length from the wire\n    let mut buf = vec![0u8; num_bytes];                               // unbounded eager allocation\n    self.transport.read_exact(&mut buf).map(|_| buf).map_err(From::from)\n}\n```\n\nThere is no check that `num_bytes` is non-negative or that it fits within the data actually available:\n\n- A length of `0x7FFFFFFF` forces a ~2 GiB allocation; `0x20000000` forces 512 MiB; and so on, from only a 4-byte input.\n- A negative length casts to a huge `usize` (up to `usize::MAX`), causing an immediate allocation failure / abort.\n\n`read_string` routes through `read_bytes`, so string fields are affected the same way. The sink is reachable from any peer sending binary-protocol data, so this is an unauthenticated, network-reachable denial of service.\n\n## The fix\n\nFrom `thrift` 0.23.0 onward, `read_bytes` goes through `read_binary_len`, which rejects negative sizes and enforces `TConfiguration::max_string_size` (default 100 MiB), alongside default message, frame, and recursion limits.\n\nA separate, related gap on the non-strict message-name path was published as CVE-2026-58389 and fixed in 0.24.0; this advisory covers the `read_bytes` unbounded allocation (CVE-2026-43868), fixed in 0.23.0.","state":0,"publishedAt":"2026-11-02T12:00:00+00:00","modifiedAt":"2026-11-02T12:10:42.3181497+00:00","affected":[{"ecosystem":"crates.io","name":"thrift","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"0.0.0-0"},{"kind":"fixed","version":"0.23.0"}]}],"versions":[],"rawVersionEvidence":null}],"metrics":[{"system":"CVSS_V3","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":null,"severity":null}],"references":["https://crates.io/crates/thrift","https://rustsec.org/advisories/RUSTSEC-2026-0435.html","https://lists.apache.org/thread/zj76dtwnbbs1m7z3focf4wd51pqpsmn9"],"sourceUrl":"https://osv.dev/vulnerability/RUSTSEC-2026-0435","license":"OSV · upstream source license applies","key":"osv:RUSTSEC-2026-0435","identifiers":["RUSTSEC-2026-0435","BIT-thrift-2026-43868","CVE-2026-43868","GHSA-2f9f-gq7v-9h6m"]},"retained":false,"historicalAffected":[]}],"coverage":[]}