CVE-2026-24783: Soroban fixed point math Soroban-fixed-point-math Has Incorrect Rounding And Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-x5m4-43jf-hh65",
  "modified" : "2026-01-28T16:18:54Z",
  "published" : "2026-01-28T16:18:54Z",
  "aliases" : [ "CVE-2026-24783" ],
  "summary" : "soroban-fixed-point-math has Incorrect Rounding and Overflow Handling in Signed Fixed-Point Math with Negatives",
  "details" : "### Impact\n\n#### Incorrect rounding direction for signed mul and div operations\n\nThe `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 $z$.\n\nThis 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`. \n\nThis error is present in all signed `FixedPoint` and `SorobanFixedPoint` implementations, including `i64`, `i128`, and `I256`.\n\n#### Negative Overflow in `i64`\n\nThe `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`.\n\nThis caused negative results smaller than `i64:MIN` to wrap around to a large positive number instead of being caught as an overflow.\n\nThis error only exists for the `FixedPoint` implementation of `i64`. \n\n### Patches\n\n* v1.3.0 users should upgrade to patch v1.3.1\n* v1.4.0 users should upgrade to patch v1.4.1\n\nAll versions `>=v1.4.1` contain the patch. \n\n### Workarounds\nThere are no known workarounds. Upgrade to the patched version.\n\n### Credits\n\nsoroban-fixed-point-math would like to thank the team at [Certora](https://www.certora.com/) for discovering and reporting the issue.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "crates.io",
      "name" : "soroban-fixed-point-math"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "1.4.0"
      }, {
        "fixed" : "1.4.1"
      } ]
    } ],
    "versions" : [ "1.4.0" ]
  }, {
    "package" : {
      "ecosystem" : "crates.io",
      "name" : "soroban-fixed-point-math"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "1.3.0"
      }, {
        "fixed" : "1.3.1"
      } ]
    } ],
    "versions" : [ "1.3.0" ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/script3/soroban-fixed-point-math/security/advisories/GHSA-x5m4-43jf-hh65"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-24783"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/script3/soroban-fixed-point-math/commit/c9233f7094198a49ed66a4d75786a8a3755c936a"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/script3/soroban-fixed-point-math"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/script3/soroban-fixed-point-math/releases/tag/v1.3.1"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/script3/soroban-fixed-point-math/releases/tag/v1.4.1"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-682" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-01-28T16:18:54Z",
    "nvd_published_at" : "2026-01-27T22:15:57Z"
  }
}