{"id":"RUSTSEC-2026-0432","summary":"`codeq`: decoding untrusted input can allocate memory from an unchecked length prefix (denial of service)","details":"`codeq` is a serialization library whose `Decode` trait reads length-prefixed values. For `String` and `Vec\u003cu8\u003e`, the length-prefixed `Decode` implementations read a 4-byte big-endian length and allocate a buffer of that size **before** reading the payload. Because the declared length is taken straight from the input with no upper bound and no cross-check against the bytes actually available, a tiny input can force an allocation of up to ~4 GiB. Code that decodes untrusted data through `codeq` can therefore be made to spike memory use and be OOM-killed (CWE-400, uncontrolled resource consumption).\n\nThe affected path, in `src/codec/impls/string_impl.rs`:\n\n```rust\nimpl Decode for String {\n    fn decode\u003cR: io::Read\u003e(mut r: R) -\u003e Result\u003cSelf, io::Error\u003e {\n        let len = r.read_u32::\u003cBigEndian\u003e()? as usize;\n        let mut buf = vec![0; len];   // allocates `len` bytes up front\n        r.read_exact(&mut buf)?; \n        String::from_utf8(buf).map_err(|e| io::Error::new(io::ErrorKind::InvalidData, e))\n    }\n}\n```\n\nAny code that decodes attacker-controlled bytes through `codeq` can be forcedcto allocate up to ~4 GiB per `decode` call from a 4-byte length prefix. On a service decoding untrusted input this is a cheap denial of service (crash / OOM-kill). The practical severity depends on how the embedding wires `codeq` to untrusted bytes.\n\n## Remediation\n\nFixed in `0.6.3`, which grows the decode buffers as payload bytes actually arrive instead of pre-allocating the full declared length (commit `9f15313`, \"fix: codec: grow decode buffers as payload bytes arrive\"). Upgrade to `codeq \u003e= 0.6.3`.","modified":"2026-11-02T11:30:16.809391425Z","published":"2026-10-31T12:00:00Z","database_specific":{"license":"CC0-1.0"},"references":[{"type":"PACKAGE","url":"https://crates.io/crates/codeq"},{"type":"ADVISORY","url":"https://rustsec.org/advisories/RUSTSEC-2026-0432.html"},{"type":"REPORT","url":"https://github.com/drmingdrmer/codeq/issues/4"}],"affected":[{"package":{"name":"codeq","ecosystem":"crates.io","purl":"pkg:cargo/codeq"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0.0.0-0"},{"fixed":"0.6.3"}]}],"ecosystem_specific":{"affects":{"functions":[],"arch":[],"os":[]},"affected_functions":null},"database_specific":{"categories":["denial-of-service"],"source":"https://github.com/rustsec/advisory-db/blob/osv/crates/RUSTSEC-2026-0432.json","cvss":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","informational":null}}],"schema_version":"1.9.2","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"}]}