ALPINE-CVE-2026-33636
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.
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