{
  "affected": [
    {
      "affectedData": [
        {
          "product": "Pillow",
          "vendor": "python-pillow",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 8.2.0, \u003c 13.0.0"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Pillow is a Python imaging library. From 8.2.0 until 13.0.0, Pillow\u0027s tiled-TIFF decoder can read past the tile buffer while copying four-byte pixels. In _decodeTile, libtiff can return a tile allocation smaller than the required row stride multiplied by the tile length, and Pillow\u0027s stride-and-copy loop walks beyond that allocation. An attacker can supply a crafted tiled TIFF to an application that loads it. This can expose adjacent heap data in pixels or crash the process. This issue is fixed in version 13.0.0."
    }
  ],
  "id": "CVE-2026-112395",
  "lastModified": "2026-10-20T19:48:50.250",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "LOW",
          "baseScore": 6.5,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "LOW",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 2.5,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-10-19T21:17:07.880",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/python-pillow/Pillow/commit/76869efdbbf2ad7dccd7536520fb61b7a00ab61e"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/python-pillow/Pillow/releases/tag/13.0.0"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/python-pillow/Pillow/security/advisories/GHSA-462x-pgg6-55fp"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Undergoing Analysis",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-122"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Primary"
    }
  ]
}

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "pillow"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "8.2.0"
            },
            {
              "fixed": "13.0.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-112395"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-122"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-10-20T20:49:26Z",
    "nvd_published_at": "2026-10-19T21:17:07Z",
    "severity": "MODERATE"
  },
  "details": "### Summary\n\nPillow\u0027s libImaging `_decodeTile` decoder, used to decode tiled TIFF images, allocates a per-tile buffer using `realloc(state-\u003ebuffer, TIFFTileSize(tiff))`. After each `TIFFReadTile` it then iterates `tile_y` from 0 up to `current_tile_length` and calls the configured row unpacker (here `copy4`) with the source pointer `state-\u003ebuffer + tile_y * row_byte_size`. When libtiff returns a `tile_bytes_size` smaller than the worst-case `row_byte_size * tile_length`, the inner stride-and-copy loop walks past the realloc\u0027d region and `copy4` performs a 1024-byte `memcpy` that reads up to `(tile_length-1) * row_byte_size + row_byte_size` bytes from a buffer sized only to `tile_bytes_size`. The supplied PoC TIFF triggers a 1024-byte over-read exactly 0 bytes past a 196608-byte allocation. An attacker who can convince a Pillow-using application to decode a crafted TIFF can trigger a process crash (DoS) and may cause adjacent heap memory to be copied into the decoded pixel buffer.\n\n### Details\n\nPillow\u0027s TIFF decoder, when libtiff reports the file is tiled, takes the `_decodeTile` path. The function:\n\n1. Asks libtiff for `TIFFTileSize(tiff)` (the bytes-per-tile) and `TIFFTileRowSize(tiff)` (the bytes per row *as stored by libtiff*).\n2. Reallocates `state-\u003ebuffer` to exactly `tile_bytes_size`.\n3. For each tile origin `(x, y)` and each plane, calls `TIFFReadTile` into `state-\u003ebuffer`, then walks the tile row by row, calling the configured `ImagingShuffler` (here `copy4`) on each row\u0027s worth of source bytes.\n\nThe validation done before the loop is:\n\n```c\nif (tile_bytes_size \u003e ((tile_length * state-\u003ebits / planes + 7) / 8) * tile_width) {\n    state-\u003eerrcode = IMAGING_CODEC_BROKEN;\n    return -1;\n}\n```\n\nThis rejects oversized libtiff tiles, but it does **not** reject *undersized* ones \u2014 i.e. the case where libtiff returns a `tile_bytes_size` strictly **less** than `row_byte_size * tile_length`. The loop body, however, indexes into the buffer assuming the buffer is at least `row_byte_size * tile_length` bytes long.\n\n### Vulnerable Code\n\n```c\n// src/libImaging/TiffDecode.c:446-490 \u2014 _decodeTile\nnew_data = realloc(state-\u003ebuffer, state-\u003ebytes);   // bytes = tile_bytes_size\nif (!new_data) { ... }\nstate-\u003ebuffer = new_data;\n\nfor (y = state-\u003eyoff; y \u003c state-\u003eysize; y += tile_length) {\n    for (plane = 0; plane \u003c planes; plane++) {\n        ImagingShuffler shuffler = unpackers[plane];\n        for (x = state-\u003exoff; x \u003c state-\u003exsize; x += tile_width) {\n            if (TIFFReadTile(tiff, (tdata_t)state-\u003ebuffer, x, y, 0, plane) == -1) { ... }\n\n            current_tile_width  = min((INT32)tile_width,  state-\u003exsize - x);\n            current_tile_length = min((INT32)tile_length, state-\u003eysize - y);\n            for (tile_y = 0; tile_y \u003c current_tile_length; tile_y++) {\n                shuffler(\n                    (UINT8 *)im-\u003eimage[tile_y + y] + x * im-\u003epixelsize,\n                    state-\u003ebuffer + tile_y * row_byte_size,   // \u003c-- OOB stride\n                    current_tile_width\n                );\n            }\n        }\n    }\n}\n```\n\n```c\n// src/libImaging/Unpack.c:1288-1291 \u2014 copy4 (the crash site)\nstatic void\ncopy4(UINT8 *out, const UINT8 *in, int pixels) {\n    /* RGBA, CMYK quadruples */\n    memcpy(out, in, 4 * pixels);   // \u003c-- ASAN-detected READ here\n}\n```\n\nThe PoC\u0027s tile metadata yields `tile_width = tile_length = 256`, `row_byte_size = 1024` (4 bytes/pixel \u00d7 256 pixels), and `tile_bytes_size = 196608` (which is 256\u00b7256\u00b73 = three-channel-byte storage). The realloc\u0027d buffer is 196608 bytes. The unpacker iterates `tile_y` from 0 to 255 and for the highest rows the source pointer `state-\u003ebuffer + tile_y * 1024` already lies at or past offset 196608 \u2014 the very last row\u0027s `memcpy(in=buffer+255\u00b71024, 1024)` reads 1024 bytes starting `260096 - 196608 = 63488` bytes past the allocation; ASAN flags the very first byte past the heap region (`READ of size 1024 at \u2026 0 bytes after 196608-byte region`).\n\nThe mismatch is real: libtiff\u0027s `TIFFTileSize` returns the *packed* per-tile storage (which depends on the file\u0027s photometric/separation layout \u2014 it can legitimately be smaller than `row_byte_size \u00d7 tile_length`), while the inner loop strides as if the buffer always equals `row_byte_size \u00d7 tile_length`.\n\n\n## Attribution\n\nThis issue was found by Anthropic from using Claude to study security of open source projects, and I am from Ada Logics helping validate the found issues and report to maintainers. The data in this report has been reviewed manually.",
  "id": "GHSA-462x-pgg6-55fp",
  "modified": "2026-10-20T20:49:27Z",
  "published": "2026-10-20T20:49:26Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/python-pillow/Pillow/security/advisories/GHSA-462x-pgg6-55fp"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-112395"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python-pillow/Pillow/commit/76869efdbbf2ad7dccd7536520fb61b7a00ab61e"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/python-pillow/Pillow"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python-pillow/Pillow/releases/tag/13.0.0"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Pillow tiled-TIFF decoder reads past tile buffer in copy4 (Unpack.c:1290)"
}