{"id":"RUSTSEC-2026-0486","summary":"xattr functions mark unwritten bytes as initialized when given a zero-length buffer","details":"The extended-attribute functions in `rustix::fs` (`getxattr`, `lgetxattr`, `fgetxattr`, `listxattr`, `llistxattr` and `flistxattr`) write into a `Buffer` and then mark as many bytes initialized as the system call reported. When the buffer has zero length, the operating system treats the call as a size query: it writes nothing and returns the size of the attribute value or of the name list. rustix still marked that many bytes as initialized.\n\nPassing a `Vec` whose length equals its capacity through `spare_capacity` gives such a zero-length buffer, and rustix then set the vector's length past its capacity over memory that was never written. This is undefined behavior reachable from safe code. With an empty `&mut [MaybeUninit\u003cu8\u003e]` the call panics instead.\n\nFrom 1.1.6 these functions return an empty result for a zero-length buffer, and new `getxattr_query`, `lgetxattr_query`, `fgetxattr_query`, `listxattr_query`, `llistxattr_query` and `flistxattr_query` functions return the size. The 0.38 series did not have the `Buffer` API and is not affected.","aliases":["GHSA-jh2m-fhpj-3vr7"],"modified":"2026-11-11T08:45:02.466292839Z","published":"2026-10-27T12:00:00Z","database_specific":{"license":"CC0-1.0"},"references":[{"type":"PACKAGE","url":"https://crates.io/crates/rustix"},{"type":"ADVISORY","url":"https://rustsec.org/advisories/RUSTSEC-2026-0486.html"},{"type":"WEB","url":"https://github.com/bytecodealliance/rustix/commit/8e6aaa6713d2bb64b1fdd8c472e3a32a10a76d70"}],"affected":[{"package":{"name":"rustix","ecosystem":"crates.io","purl":"pkg:cargo/rustix"},"ranges":[{"type":"SEMVER","events":[{"introduced":"1.0.0"},{"fixed":"1.1.6"}]}],"ecosystem_specific":{"affects":{"arch":[],"os":[],"functions":["rustix::fs::fgetxattr","rustix::fs::flistxattr","rustix::fs::getxattr","rustix::fs::lgetxattr","rustix::fs::listxattr","rustix::fs::llistxattr"]},"affected_functions":null},"database_specific":{"informational":"unsound","categories":[],"cvss":null,"source":"https://github.com/rustsec/advisory-db/blob/osv/crates/RUSTSEC-2026-0486.json"}}],"schema_version":"1.9.2"}