UnsoundRUSTSEC-2026-0135 · diesel
RUSTSEC-2026-0135: Unsound transmute while debug/display printing batch Insert statements in Diesel's SQLite backend
Short answerdiesel has an API that can cause undefined behaviour from safe code: Unsound transmute while debug/display printing batch Insert statements in Diesel's SQLite backend. Fixed in 2.3.8.
| Crate | diesel |
|---|---|
| Type | Unsound |
| Affected versions | Before 2.3.8. |
| Fixed in | 2.3.8 |
| Severity | not scored |
| Published | 2026-04-24 |
| Last changed | 2026-05-13 |
| Also known as | none |
| Affected functions | diesel::debug_query |
What to do
- See which version you have:
cargo tree -i diesel(it also shows which of your dependencies pulls it in). - Update within your version requirement:
cargo update -p diesel. If the fix is a newer major or minor than your requirement allows, raise it in Cargo.toml (for examplediesel = "2.3.8") or update the dependency that pulls it in. - Check again with
cargo audit, or paste your Cargo.lock into our Cargo.toml checker.
Details from the advisory
Diesel allows users to output the generated SQL for any query DSL construct via th diesel::debug_query function as Display and Debug output.
For the particular implementation used by batch Insert statements in the SQLite backend Diesel relied on an unspecified transmute between types with a #[repr(rust)] layout. This is formally undefined behaviour as the compiler is free to change the layout of these types at any time.
This vulnerability affects users that print out batch insert statements constructed using an array/vector of values without default values using diesel::debug_query on the SQLite backend.
Mitigation
The preferred mitigation to the outlined problem is to update to Diesel version 2.3.8 or newer, which includes fixes for the problem.
Resolution
Diesel now uses a sound cast instead.
References
- Package: crates.io/crates/diesel
- Advisory: rustsec.org/advisories/RUSTSEC-2026-0135.html
- Web: github.com/diesel-rs/diesel/pull/5042
From the RustSec Advisory Database (CC0-1.0) via the OSV export, downloaded Oct 24, 2026. Severity score computed from the published CVSS vector.
Other advisories for diesel
- Vulnerability CriticalRUSTSEC-2021-0037 · 2021-03-05Fix a use-after-free bug in diesels Sqlite backend
- VulnerabilityRUSTSEC-2024-0365 · 2024-08-23Binary Protocol Misinterpretation caused by Truncating or Overflowing Casts
- UnsoundRUSTSEC-2026-0111 · 2026-04-24Possible UTF-8 corruption in Diesels SQLite backend
- UnsoundRUSTSEC-2026-0134 · 2026-04-24Unsound access to padding bytes while serializing date/time values using the Mysql backend
- VulnerabilityRUSTSEC-2026-0136 · 2026-04-24Command injection in Diesel's implementation of `COPY FROM`/`COPY TO`
- VulnerabilityRUSTSEC-2026-0137 · 2026-04-24Possible unaligned data access for implementations of `SqliteAggregate`
- UnsoundRUSTSEC-2026-0172 · 2026-06-05Possible use after free when deserializing a SQLite database via `SqliteConnection::deserialize_readonly_database`
Up next
Same cratediesel: security historyEvery advisory for this crate, and whether it is safe to use today.Read it next →Did this answer your question?