LowFix available
libsixel — security advisory
libsixel is a SIXEL encoder/decoder implementation derived from kmiya's sixel. From to 1.8.7-r1, a wrong NULL check after an allocation call in sixel_decode_raw and sixel_decode causes a NULL pointer dereference whenever the allocation fails. The check tests the address of the output parameter (always non-NULL) instead of the value the malloc returned. On allocation failure, the function continues and writes through a NULL pointer, crashing the process. This is a denial of service against any caller of these public APIs that hits a low-memory condition. This vulnerability is fixed in 1.8.7-r2.
- Products
- libsixel
- Affected versions
- 1.10.3-3, 1.10.5-1, 1:1.8.7-1, 1:1.8.7-2, 1:1.8.7-3, 1:1.8.7-4, 1:1.8.7-5, 1:1.8.7-6, 1:1.8.7-r2-1
- Fixed versions
- 1:1.8.7-r2-1
- CVEs
- CVE-2026-44638
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 17:48 UTC · Revision 2
Source evidence
libsixel is a SIXEL encoder/decoder implementation derived from kmiya's sixel. From to 1.8.7-r1, a wrong NULL check after an allocation call in sixel_decode_raw and sixel_decode causes a NULL pointer dereference whenever the allocation fails. The check tests the address of the output parameter (always non-NULL) instead of the value the malloc returned. On allocation failure, the function continues and writes through a NULL pointer, crashing the process. This is a denial of service against any caller of these public APIs that hits a low-memory condition. This vulnerability is fixed in 1.8.7-r2.
osv:DEBIAN-CVE-2026-44638
libsixel
Fixed versions: Not specified
libsixel
Fixed versions: Not specified
libsixel
Fixed versions: 1:1.8.7-r2-1
Complete source record
{
"id": "75c5c99630d128270e76084476f905882cd3928d7003305a7713d2bece2618e1",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2026-44638",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2026-44638",
"summary": "libsixel is a SIXEL encoder/decoder implementation derived from kmiya's sixel. From to 1.8.7-r1, a wrong NULL check after an allocation call in sixel_decode_raw and sixel_decode causes a NULL pointer dereference whenever the allocation fails. The check tests the address of the output parameter (always non-NULL) instead of the value the malloc returned. On allocation failure, the function continues and writes through a NULL pointer, crashing the process. This is a denial of service against any caller of these public APIs that hits a low-memory condition. This vulnerability is fixed in 1.8.7-r2.",
"evidence": "osv:DEBIAN-CVE-2026-44638",
"products": [
{
"name": {
"value": "libsixel",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "1.10.3-3",
"evidence": "/affected/0/versions"
},
{
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"evidence": "/affected/0/versions"
},
{
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"evidence": "/affected/0/versions"
},
{
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},
{
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{
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{
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{
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{
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{
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{
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{
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{
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{
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},
{
"name": {
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},
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{
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"evidence": "/affected/2/versions"
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{
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{
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{
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{
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"evidence": "/affected/2/versions"
},
{
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],
"severity": "low",
"structured": {
"id": "DEBIAN-CVE-2026-44638",
"aliases": [
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],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:L"
}
],
"affected": [
{
"ranges": [
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"events": [
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"package": {
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"ecosystem": "Debian:12"
},
"versions": [
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},
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{
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"package": {
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"purl": "pkg:deb/debian/libsixel?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"versions": [
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"1:1.8.7-1",
"1:1.8.7-2",
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"1:1.8.7-4",
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],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-44638.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
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{
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}
],
"package": {
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"purl": "pkg:deb/debian/libsixel?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"versions": [
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"1:1.8.7-1",
"1:1.8.7-2",
"1:1.8.7-3",
"1:1.8.7-4",
"1:1.8.7-5",
"1:1.8.7-6"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-44638.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
],
"modified": "2026-10-27T09:47:36.475937690Z",
"provider": "osv",
"upstream": [
"CVE-2026-44638"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2026-44638"
]
},
"related_cves": [
{
"value": "CVE-2026-44638",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 461257,
"published_at": "2026-05-14T20:17:08.983+00:00"
}