CVE-2026-24783
soroban-fixed-point-math has Incorrect Rounding and Overflow Handling in Signed Fixed-Point Math with Negatives
Impact
### Impact #### Incorrect rounding direction for signed mul and div operations The `mulDiv(x, y, z)` function incorrectly handled cases where both the intermediate product $x * y$ and the divisor $z$ were negative. The logic assumed that if the intermediate product was negative, the final result must also be negative, neglecting the sign of $z$. This resulted in rounding being applied in the wrong direction for cases where both $x * y$ and $z$ were negative. The functions most at risk are `fixed_div_floor` and `fixed_div_ceil`, as they often use non-constant numbers as the divisor $z$ in `mulDiv`. This error is present in all signed `FixedPoint` and `SorobanFixedPoint` implementations, including `i64`, `i128`, and `I256`. #### Negative Overflow in `i64` The `mulDiv(x, y, z)` function for `i64` used the `i128` type to handle "phantom overflows". These are overflows that occur intermediately during a calculation, like when computing the intermediate product $x * y$. When the final result of `mulDiv` was computed in `i128`, it was scaled back down to `i64` before returning. While the code verified that the result did not exceed `i64::MAX`, it did not check against `i64::MIN`. This caused negative results smaller than `i64:MIN` to wrap around to a large positive number instead of being caught as an overflow. This error only exists for the `FixedPoint` implementation of `i64`. ### Patches * v1.3.0 users should upgrade to patch v1.3.1 * v1.4.0 users should upgrade to patch v1.4.1 All versions `>=v1.4.1` contain the patch. ### Workarounds There are no known workarounds. Upgrade to the patched version. ### Credits soroban-fixed-point-math would like to thank the team at [Certora](https://www.certora.com/) for discovering and reporting the issue.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| rust | soroban-fixed-point-math | = 1.4.0 | 1.4.1 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Script3 | Soroban-Fixed-Point-Math | Versions 1.3.0, 1.4.0 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/script3/soroban-fixed-point-math/commit/c9233f7094198a49ed66a4d75786a8a3755c936a
- https://github.com/script3/soroban-fixed-point-math/releases/tag/v1.3.1
- https://github.com/script3/soroban-fixed-point-math/releases/tag/v1.4.1
- https://github.com/script3/soroban-fixed-point-math/security/advisories/GHSA-x5m4-43jf-hh65
- https://github.com/advisories/GHSA-x5m4-43jf-hh65
- https://nvd.nist.gov/vuln/detail/CVE-2026-24783