github-actions[bot] opened a new issue, #2103: URL: https://github.com/apache/iceberg-rust/issues/2103
> Integer overflow in `BytesMut::reserve` | Details | | | ------------------- | ---------------------------------------------- | | Package | `bytes` | | Version | `1.11.0` | | URL | [https://github.com/advisories/GHSA-434x-w66g-qw3r](https://github.com/advisories/GHSA-434x-w66g-qw3r) | | Date | 2026-02-03 | | Patched versions | `>=1.11.1` | | Unaffected versions | `<1.2.1` | In the unique reclaim path of `BytesMut::reserve`, the condition ```rs if v_capacity >= new_cap + offset ``` uses an unchecked addition. When `new_cap + offset` overflows `usize` in release builds, this condition may incorrectly pass, causing `self.cap` to be set to a value that exceeds the actual allocated capacity. Subsequent APIs such as `spare_capacity_mut()` then trust this corrupted `cap` value and may create out-of-bounds slices, leading to UB. This behavior is observable in release builds (integer overflow wraps), whereas debug builds panic due to overflow checks. ## PoC ```rs use bytes::*; fn main() { let mut a = BytesMut::from(&b"hello world"[..]); let mut b = a.split_off(5); // Ensure b becomes the unique owner of the backing storage drop(a); // Trigger overflow in new_cap + offset inside reserve b.reserve(usize::MAX - 6); // This call relies on the corrupted cap and may cause UB & HBO b.put_u8(b'h'); } ``` # Workarounds Users of `BytesMut::reserve` are only affected if integer overflow checks are configured to wrap. When integer overflow is configured to panic, this issue does not apply. See [advisory page](https://rustsec.org/advisories/RUSTSEC-2026-0007.html) for additional details. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
