{
  "affected": [
    {
      "database_specific": {
        "human_link": "https://github.com/haskell/security-advisories/tree/main/advisories/published/2026/HSEC-2026-0012.md",
        "osv": "https://raw.githubusercontent.com/haskell/security-advisories/refs/heads/generated/osv-export/2026/HSEC-2026-0012.json",
        "source": "https://github.com/haskell/security-advisories/blob/generated/osv-export/2026/HSEC-2026-0012.json"
      },
      "package": {
        "ecosystem": "Hackage",
        "name": "scientific",
        "purl": "pkg:hackage/scientific"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.3.9.0"
            },
            {
              "fixed": "0.3.10.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "severity": [
        {
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H",
          "type": "CVSS_V3"
        }
      ],
      "versions": [
        "0.3.9.0"
      ]
    }
  ],
  "database_specific": {
    "home": "https://github.com/haskell/security-advisories",
    "osvs": "https://raw.githubusercontent.com/haskell/security-advisories/refs/heads/generated/osv-export",
    "repository": "https://github.com/haskell/security-advisories"
  },
  "details": "# Out-of-bounds read in Eq and Ord on numbers with extreme exponents\n\n`scientific-0.3.9.0` reimplemented `Eq` and `Ord` without normalising their\narguments. The new implementation short-circuits on\n`integerLog10' c + e` computed in `Int`, which overflows when the base-10\nexponent is close to `maxBound :: Int`. The overflowed comparison then falls\nthrough to `magnitude (e1 - e2)`, where the exponent difference overflows to a\nnegative `Int` as well. `magnitude` indexed its cached power-of-ten array\nwithout a bounds check, so the negative index performed an out-of-bounds read\nand the process died with `SIGSEGV`.\n\nWith `scientific-0.3.9.0` (GHC 9.10.3, x86_64-linux), as reported in\n[basvandijk/scientific#120](https://github.com/basvandijk/scientific/issues/120):\n\n```haskell\nimport Data.Scientific\n\nmain :: IO ()\nmain = print (scientific 10 maxBound == scientific 1 minBound)\n```\n\n```\n$ ./repro; echo \"exit=$?\"\nexit=139\n```\n\nThe issue was discovered when Stackage nightly test suites\n(`genvalidity-hspec-aeson`, `genvalidity-sydtest-aeson`) started segfaulting\nafter upgrading to `scientific-0.3.9.0`: their property tests round-trip\n`aeson` `Value`s, which produces `Scientific`s with extreme exponents.\n\nVersions before `0.3.9.0` did not crash, but `Eq`/`Ord` returned invalid\nresults there instead (the normalisation-based implementation overflows the\nexponent, reporting `scientific 10 maxBound == scientific 1 minBound` as\n`True`). The same unchecked read was also reachable through `(+)` and `(-)` on\nolder versions, guarded only by the documented warning about the potential\n`10^e` blowup — reading outside the cache is not.\n\n## Resolution\n\n`scientific-0.3.10.0` computes the logarithms using `Integer`, fixing both the\ncrash and the invalid comparison results, and bounds-checks `magnitude`, so a\nnegative exponent now raises an error instead of reading out of bounds. All\nentry points (`Eq`, `Ord`, `(+)`, `(-)`) are covered; upgrade to\n`scientific-0.3.10.0` or later.\n\nNote that printing values with exponents close to `maxBound :: Int` remains\nunreliable due to the inherent `Int` exponent overflow in `normalize`; this\nlimitation is documented upstream and postponed to the next major release.\n\n## Credits\n\nReported by Tom Sydney Kerckhove (@NorfairKing); fixed by Oleg Grenrus\n(@phadej).\n",
  "id": "HSEC-2026-0012",
  "modified": "2026-11-03T22:45:02.613041440Z",
  "published": "2026-11-03T22:32:58Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://github.com/basvandijk/scientific/issues/120"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/NorfairKing/validity/issues/121"
    },
    {
      "type": "FIX",
      "url": "https://github.com/basvandijk/scientific/pull/121"
    },
    {
      "type": "DISCUSSION",
      "url": "https://www.reddit.com/r/haskell/comments/1xbj59g/dont_use_scientific_for_calculations_it_can/"
    }
  ],
  "related": [
    "HSEC-2026-0011"
  ],
  "schema_version": "1.9.2",
  "summary": "Out-of-bounds read in Eq and Ord on numbers with extreme exponents"
}