CVE-2026-24783

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.

Workarounds

There are no known workarounds. Upgrade to the patched version.

Credits

soroban-fixed-point-math would like to thank the team at Certora for discovering and reporting the issue.

CVE-2026-24783 has a CVSS score of 7.5 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.4.1, 1.3.1); upgrading removes the vulnerable code path.

Kodem intelligence

• 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.

1. What is CVE-2026-24783? CVE-2026-24783 is a high-severity security vulnerability in soroban-fixed-point-math (rust), affecting versions = 1.4.0. It is fixed in 1.4.1, 1.3.1.
2. How severe is CVE-2026-24783? CVE-2026-24783 has a CVSS score of 7.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of soroban-fixed-point-math are affected by CVE-2026-24783? soroban-fixed-point-math (rust) versions = 1.4.0 is affected.
4. Is there a fix for CVE-2026-24783? Yes. CVE-2026-24783 is fixed in 1.4.1, 1.3.1. Upgrade to this version or later.
5. Is CVE-2026-24783 exploitable, and should I be worried? Whether CVE-2026-24783 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-24783 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-24783?
   • Upgrade soroban-fixed-point-math to 1.4.1 or later
   • Upgrade soroban-fixed-point-math to 1.3.1 or later