{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-27809",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-02-26T15:17:16.249743Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-02-26T15:17:34.807Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "psd-tools",
          "vendor": "psd-tools",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 1.12.2"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "psd-tools is a Python package for working with Adobe Photoshop PSD files. Prior to version 1.12.2, when a PSD file contains malformed RLE-compressed image data (e.g. a literal run that extends past the expected row size), decode_rle() raises ValueError which propagated all the way to the user, crashing psd.composite() and psd-tools export. decompress() already had a fallback that replaces failed channels with black pixels when result is None, but it never triggered because the ValueError from decode_rle() was not caught. The fix in version 1.12.2 wraps the decode_rle() call in a try/except so the existing fallback handles the error gracefully."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 6.8,
            "baseSeverity": "MEDIUM",
            "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:H/VA:H/SC:N/SI:N/SA:N/E:U",
            "version": "4.0",
            "vulnAvailabilityImpact": "HIGH",
            "vulnConfidentialityImpact": "NONE",
            "vulnIntegrityImpact": "HIGH"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-409",
              "description": "CWE-409: Improper Handling of Highly Compressed Data (Data Amplification)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-789",
              "description": "CWE-789: Memory Allocation with Excessive Size Value",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-617",
              "description": "CWE-617: Reachable Assertion",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-190",
              "description": "CWE-190: Integer Overflow or Wraparound",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-755",
              "description": "CWE-755: Improper Handling of Exceptional Conditions",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-704",
              "description": "CWE-704: Incorrect Type Conversion or Cast",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-02-25T23:57:00.760Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/psd-tools/psd-tools/security/advisories/GHSA-24p2-j2jr-386w",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/psd-tools/psd-tools/security/advisories/GHSA-24p2-j2jr-386w"
        },
        {
          "name": "https://github.com/psd-tools/psd-tools/commit/6c0a78f195b5942757886a1863793fd5946c1fb1",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/psd-tools/psd-tools/commit/6c0a78f195b5942757886a1863793fd5946c1fb1"
        },
        {
          "name": "https://github.com/psd-tools/psd-tools/releases/tag/v1.12.2",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/psd-tools/psd-tools/releases/tag/v1.12.2"
        }
      ],
      "source": {
        "advisory": "GHSA-24p2-j2jr-386w",
        "discovery": "UNKNOWN"
      },
      "title": "psd-tools: Compression module has unguarded zlib decompression, missing dimension validation, and hardening gaps"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-27809",
    "datePublished": "2026-02-25T23:57:00.760Z",
    "dateReserved": "2026-02-24T02:31:33.267Z",
    "dateUpdated": "2026-02-26T15:17:34.807Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "psd-tools"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.12.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-27809"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-190",
      "CWE-409",
      "CWE-617",
      "CWE-704",
      "CWE-755",
      "CWE-789"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-02-26T15:20:51Z",
    "nvd_published_at": "2026-02-26T00:16:26Z",
    "severity": "MODERATE"
  },
  "details": "## Summary\n\nA security review of the `psd_tools.compression` module (conducted against the `fix/invalid-rle-compression` branch, commits `7490ffa`\u2013`2a006f5`) identified the following pre-existing issues. The two findings introduced and **fixed** by those commits (Cython buffer overflow, `IndexError` on lone repeat header) are excluded from this report.\n\n---\n\n## Findings\n\n### 1. Unguarded `zlib.decompress` \u2014 ZIP bomb / memory exhaustion (Medium)\n\n**Location**: `src/psd_tools/compression/__init__.py`, lines 159 and 162\n\n```python\nresult = zlib.decompress(data)          # Compression.ZIP\ndecompressed = zlib.decompress(data)    # Compression.ZIP_WITH_PREDICTION\n```\n\n`zlib.decompress` is called without a `max_length` cap. A crafted PSD file containing a ZIP-compressed channel whose compressed payload expands to gigabytes would exhaust process memory before any limit is enforced. The RLE path is not vulnerable to this because the decoder pre-allocates exactly `row_size \u00d7 height` bytes; the ZIP path has no equivalent ceiling.\n\n**Impact**: Denial-of-service / OOM crash when processing untrusted PSD files.\n\n**Suggested mitigation**: Pass a reasonable `max_length` to `zlib.decompress`, derived from the expected `width * height * depth // 8` byte count already computed in `decompress()`.\n\n---\n\n### 2. No upper-bound validation on image dimensions before allocation (Low)\n\n**Location**: `src/psd_tools/compression/__init__.py`, lines 138 and 193\n\n```python\nlength = width * height * max(1, depth // 8)   # decompress()\nrow_size = max(width * depth // 8, 1)           # decode_rle()\n```\n\nNeither `width`, `height`, nor `depth` are range-checked before these values drive memory allocation. The PSD format (version 2 / PSB) permits dimensions up to 300,000 \u00d7 300,000 pixels; a 4-channel 32-bit image at that size would require ~144 TB to hold. While the OS/Python allocator will reject such a request, there is no early, explicit guard that produces a clean, user-facing error.\n\n**Impact**: Uncontrolled allocation attempt from a malformed or adversarially crafted PSB file; hard crash rather than a recoverable error.\n\n**Suggested mitigation**: Validate `width`, `height`, and `depth` against known PSD/PSB limits before entering decompression, and raise a descriptive `ValueError` early.\n\n---\n\n### 3. `assert` used as a runtime integrity check (Low)\n\n**Location**: `src/psd_tools/compression/__init__.py`, line 170\n\n```python\nassert len(result) == length, \"len=%d, expected=%d\" % (len(result), length)\n```\n\nThis assertion can be silently disabled by running the interpreter with `-O` (or `-OO`), which strips all `assert` statements. If the assertion ever becomes relevant (e.g., after future refactoring), disabling it would allow a length mismatch to propagate silently into downstream image compositing.\n\n**Impact**: Loss of an integrity guard in optimised deployments.\n\n**Suggested mitigation**: Replace with an explicit `if` + `raise ValueError(...)`.\n\n---\n\n### 4. `cdef int` indices vs. `Py_ssize_t size` type mismatch in Cython decoder (Low)\n\n**Location**: `src/psd_tools/compression/_rle.pyx`, lines 18\u201320\n\n```cython\ncdef int i = 0\ncdef int j = 0\ncdef int length = data.shape[0]\n```\n\nAll loop indices are C `signed int` (32-bit). The `size` parameter is `Py_ssize_t` (64-bit on modern platforms). The comparison `j \u003c size` promotes `j` to `Py_ssize_t`, but if `j` wraps due to a row size exceeding `INT_MAX` (~2.1 GB), the resulting comparison is undefined behaviour in C. In practice, row sizes are bounded by PSD/PSB dimension limits and are unreachable at this scale; however, the mismatch is a latent defect if the function is ever called directly with large synthetic inputs.\n\n**Impact**: Theoretical infinite loop or UB at \u003e2 GB row sizes; not reachable from standard PSD/PSB parsing.\n\n**Suggested mitigation**: Change `cdef int i`, `j`, `length` to `cdef Py_ssize_t`.\n\n---\n\n### 5. Silent data degradation not surfaced to callers (Informational)\n\n**Location**: `src/psd_tools/compression/__init__.py`, lines 144\u2013157\n\nThe tolerant RLE decoder (introduced in `2a006f5`) replaces malformed channel data with zero-padded (black) pixels and emits a `logger.warning`. This is the correct trade-off over crashing, but the warning is only observable if the caller has configured a log handler. The public `PSDImage` API does not surface channel-level decode failures to the user in any other way.\n\n**Impact**: A user parsing a silently corrupt file gets a visually wrong image with no programmatic signal to check.\n\n**Suggested mitigation**: Consider exposing a per-channel decode-error flag or raising a distinct warning category that users can filter or escalate via the `warnings` module.\n\n---\n\n### 6. `encode()` zero-length return type inconsistency in Cython (Informational)\n\n**Location**: `src/psd_tools/compression/_rle.pyx`, lines 66\u201367\n\n```cython\nif length == 0:\n    return data   # returns a memoryview, not an explicit std::string\n```\n\nAll other return paths return an explicit `cdef string result`. This path returns `data` (a `const unsigned char[:]` memoryview) and relies on Cython\u0027s implicit coercion to `bytes`. It is functionally equivalent today but is semantically inconsistent and fragile if Cython\u0027s coercion rules change in a future version.\n\n**Impact**: Potential silent breakage in future Cython versions; not a current security issue.\n\n**Suggested mitigation**: Replace `return data` with `return result` (the already-declared empty `string`).\n\n---\n\n## Environment\n\n- Branch: `fix/invalid-rle-compression`\n- Reviewed commits: `7490ffa`, `2a006f5`\n- Python: 3.x (Cython extension compiled for CPython)",
  "id": "GHSA-24p2-j2jr-386w",
  "modified": "2026-02-26T15:20:51Z",
  "published": "2026-02-26T15:20:51Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/psd-tools/psd-tools/security/advisories/GHSA-24p2-j2jr-386w"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-27809"
    },
    {
      "type": "WEB",
      "url": "https://github.com/psd-tools/psd-tools/commit/6c0a78f195b5942757886a1863793fd5946c1fb1"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/psd-tools/psd-tools"
    },
    {
      "type": "WEB",
      "url": "https://github.com/psd-tools/psd-tools/releases/tag/v1.12.2"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N/E:U",
      "type": "CVSS_V4"
    }
  ],
  "summary": "psd-tools: Compression module has unguarded zlib decompression, missing dimension validation, and hardening gaps"
}