CVE-2026-59991: Psd tools Psd-tools Composite/numpy Has Uncontrolled Memory Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-8q6g-vjhf-jp8m",
  "modified" : "2026-09-22T19:45:51Z",
  "published" : "2026-09-22T19:45:51Z",
  "aliases" : [ "CVE-2026-59991" ],
  "summary" : "psd-tools composite/numpy has uncontrolled memory allocation via crafted PSD geometry",
  "details" : "### Summary\n`PSDImage.composite()` (and `.numpy()`) allocate the output image buffer from the PSD's header geometry (width × height × channels × depth, and per-layer rectangles) before validating those values against the actual file contents. A tiny crafted PSD declaring huge dimensions causes a multi-gigabyte allocation. Critically, `composite()` then returns a (black) image with only a warning, no exception is raised, so a caller cannot detect or guard against it.\n\n### Impact\nOn psd-tools 1.17.2 (latest), default usage, a 49-byte PSD makes `composite()` commit ~3 GB and return successfully (warning only); `.numpy()` reaches ~7.5 GB, and the per-layer rectangle is a second lever (up to ~32 GB), all from an input under 100 bytes (input-to-commit amplification over 1000×). Because the buffer is committed before validation and no exception is thrown, any service that composites untrusted PSDs is exposed to denial of service: on a host with less RAM than the attacker-declared geometry the allocation is an unrecoverable OOM-kill. \n\n### Steps to reproduce\n```python\n# pip install psd-tools==1.17.2\nfrom psd_tools import PSDImage\npsd = PSDImage.open(\"psd-psdtools-grammar-d23.psd\")\npsd.composite()   # commits ~3 GB from a 49-byte file and returns (warning only)\n```\n\nPoC (49 bytes), reconstruct with:\n```sh\nbase64 -d > psd-psdtools-grammar-d23.psd <<'EOF'\nOEJQUwABAAAAAAAAAAYAACg4AAAXTAAIAAMAAAAAAAAAAAAAAAAAAUNIUIFU+yQtDw==\nEOF\n```\nVerify:\n```\n7d8ebf03a54393cb0359ecf4b676d1b08c9a8c6afdd06671ef406d6893cce826  psd-psdtools-grammar-d23.psd\n```\n\n### Root cause\nThe composite/numpy buffer is sized from the declared image (and per-layer) dimensions and channel/depth without checking them against the available data length or a sane maximum.\n\n### Suggested fix\nValidate the declared dimensions, channel count, and per-layer rectangles against the actual file length (and a configurable maximum pixel/byte budget) before allocating; raise an error on overflow instead of committing the buffer and returning a black image.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "psd-tools"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.17.4"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/psd-tools/psd-tools/security/advisories/GHSA-8q6g-vjhf-jp8m"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/psd-tools/psd-tools/commit/a3d9a53ad51e667b5772a4f636ca6f2e16f4b271"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/psd-tools/psd-tools"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/psd-tools/psd-tools/releases/tag/v1.17.4"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-789" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-09-22T19:45:51Z",
    "nvd_published_at" : null
  }
}