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ALPINE-CVE-2026-33636

Type: advisorySource: OSV1 source record

LIBPNG is a reference library for use in applications that read, create, and manipulate PNG (Portable Network Graphics) raster image files. In versions 1.6.36 through 1.6.55, an out-of-bounds read and write exists in libpng's ARM/AArch64 Neon-optimized palette expansion path. When expanding 8-bit paletted rows to RGB or RGBA, the Neon loop processes a final partial chunk without verifying that enough input pixels remain. Because the implementation works backward from the end of the row, the final iteration dereferences pointers before the start of the row buffer (OOB read) and writes expanded pixel data to the same underflowed positions (OOB write). This is reachable via normal decoding of attacker-controlled PNG input if Neon is enabled. Version 1.6.56 fixes the issue.

Announced Source revision 1
Original source ↗

ALPINE-CVE-2026-33636

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: osv:ALPINE-CVE-2026-33636

libpng

Source reference: /affected/0/package/name

Affected versions
Not stated in this record
Fixed versions
1.6.56-r0

Source reference: /affected/0/ranges

Prerequisites
Not stated in this record

libpng

Source reference: /affected/1/package/name

Affected versions
Not stated in this record
Fixed versions
1.6.56-r0

Source reference: /affected/1/ranges

Prerequisites
Not stated in this record

libpng

Source reference: /affected/2/package/name

Affected versions
Not stated in this record
Fixed versions
1.6.56-r0

Source reference: /affected/2/ranges

Prerequisites
Not stated in this record

libpng

Source reference: /affected/3/package/name

Affected versions
Not stated in this record
Fixed versions
1.6.56-r0

Source reference: /affected/3/ranges

Prerequisites
Not stated in this record

libpng

Source reference: /affected/4/package/name

Affected versions
Not stated in this record
Fixed versions
1.6.56-r0

Source reference: /affected/4/ranges

Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "ranges": [
      {
        "type": "ECOSYSTEM",
        "events": [
          {
            "introduced": "1.6.36"
          },
          {
            "fixed": "1.6.56-r0"
          }
        ]
      }
    ],
    "package": {
      "name": "libpng",
      "purl": "pkg:apk/alpine/libpng?arch=source",
      "ecosystem": "Alpine:v3.20"
    },
    "database_specific": {
      "source": "https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2026-33636.json"
    },
    "ecosystem_specific": {}
  },
  {
    "ranges": [
      {
        "type": "ECOSYSTEM",
        "events": [
          {
            "introduced": "1.6.36"
          },
          {
            "fixed": "1.6.56-r0"
          }
        ]
      }
    ],
    "package": {
      "name": "libpng",
      "purl": "pkg:apk/alpine/libpng?arch=source",
      "ecosystem": "Alpine:v3.21"
    },
    "database_specific": {
      "source": "https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2026-33636.json"
    },
    "ecosystem_specific": {}
  },
  {
    "ranges": [
      {
        "type": "ECOSYSTEM",
        "events": [
          {
            "introduced": "1.6.36"
          },
          {
            "fixed": "1.6.56-r0"
          }
        ]
      }
    ],
    "package": {
      "name": "libpng",
      "purl": "pkg:apk/alpine/libpng?arch=source",
      "ecosystem": "Alpine:v3.22"
    },
    "database_specific": {
      "source": "https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2026-33636.json"
    },
    "ecosystem_specific": {}
  },
  {
    "ranges": [
      {
        "type": "ECOSYSTEM",
        "events": [
          {
            "introduced": "1.6.36"
          },
          {
            "fixed": "1.6.56-r0"
          }
        ]
      }
    ],
    "package": {
      "name": "libpng",
      "purl": "pkg:apk/alpine/libpng?arch=source",
      "ecosystem": "Alpine:v3.23"
    },
    "database_specific": {
      "source": "https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2026-33636.json"
    },
    "ecosystem_specific": {}
  },
  {
    "ranges": [
      {
        "type": "ECOSYSTEM",
        "events": [
          {
            "introduced": "1.6.36"
          },
          {
            "fixed": "1.6.56-r0"
          }
        ]
      }
    ],
    "package": {
      "name": "libpng",
      "purl": "pkg:apk/alpine/libpng?arch=source",
      "ecosystem": "Alpine:v3.24"
    },
    "database_specific": {
      "source": "https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2026-33636.json"
    },
    "ecosystem_specific": {}
  }
]

Publisher severity

No explicit severity was provided.

Event
#54281 · Revision 1
Added to Heist Feed
Publisher date
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