Medium
Security advisory
An invalid read in the stb_image.h component of libsixel prior to v1.8.5 allows attackers to cause a denial of service (DOS) via a crafted PSD file.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2020-21049
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 12:34 UTC · Revision 1
Source evidence
An invalid read in the stb_image.h component of libsixel prior to v1.8.5 allows attackers to cause a denial of service (DOS) via a crafted PSD file.
osv:CVE-2020-21049
Complete source record
{
"id": "3343f8e629c726fa390bb2ecc94178c22dcec5e42c39ff2d09c8bfa0c146a2d3",
"url": "https://osv.dev/vulnerability/CVE-2020-21049",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "CVE-2020-21049",
"summary": "An invalid read in the stb_image.h component of libsixel prior to v1.8.5 allows attackers to cause a denial of service (DOS) via a crafted PSD file.",
"evidence": "osv:CVE-2020-21049",
"products": [],
"severity": "medium",
"structured": {
"id": "CVE-2020-21049",
"aliases": [
"CVE-2020-21049"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/saitoha/libsixel",
"type": "GIT",
"events": [
{
"introduced": "0"
},
{
"fixed": "933670340dcd51e41d014d83e8d693688605b773"
},
{
"fixed": "0b1e0b3f7b44233f84e5c9f512f8c90d6bbbe33d"
}
],
"database_specific": {
"extracted_events": [
{
"cpe": "cpe:2.3:a:saitoha:libsixel:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "0"
},
{
"fixed": "1.8.5"
}
],
"source": "CPE_RANGE"
},
{
"range": [
{
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],
"source": "REFERENCES_COMMIT"
},
{
"range": [
{
"fixed": "933670340dcd51e41d014d83e8d693688605b773"
}
],
"source": "REFERENCES_TAG",
"original_tag": "v1.8.5"
}
]
}
}
],
"versions": [
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"v1.8.3",
"v1.8.2",
"v1.8.1",
"v1.8.0",
"v1.7.3",
"v1.7.2",
"v1.7.1",
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"v1.5.2",
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"v1.4.12",
"v1.4.11",
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"v1.3.4",
"v1.3.3",
"v1.3.2",
"v1.3.1",
"v1.1.2",
"v1.1.1",
"v1.1.0",
"v1.0.2",
"v1.0.1",
"v1.0.0",
"v0.28.0",
"v0.27.1",
"v0.27.0",
"v0.26.0",
"v0.25.5",
"v0.25.4",
"v0.25.3",
"v0.25.2",
"v0.25.1",
"v0.25.0",
"v0.24.2",
"v0.24.0",
"v0.23.2",
"v0.23.1",
"v0.23.0",
"v0.22.3",
"v0.22.2",
"v0.22.1",
"v0.22.0",
"v0.21.1",
"v0.21.0",
"v0.20.0",
"v0.19.6",
"v0.19.5",
"v0.19.4",
"v0.19.3",
"v0.19.2",
"v0.18.0",
"v0.17.2",
"v0.17.1",
"v0.17.0",
"v0.16.1",
"v0.16.0",
"v0.15.0",
"v0.14.0"
],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2020-21049.json",
"vanir_signatures": [
{
"id": "CVE-2020-21049-300c1a47",
"digest": {
"length": 167,
"function_hash": "14053531760985046976932775092926153829"
},
"source": "https://github.com/saitoha/libsixel/commit/0b1e0b3f7b44233f84e5c9f512f8c90d6bbbe33d",
"target": {
"file": "src/allocator.c",
"function": "sixel_allocator_calloc"
},
"deprecated": false,
"signature_type": "Function",
"signature_version": "v1"
},
{
"id": "CVE-2020-21049-7516b542",
"digest": {
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"function_hash": "248279636798139373860926751670000785549"
},
"source": "https://github.com/saitoha/libsixel/commit/0b1e0b3f7b44233f84e5c9f512f8c90d6bbbe33d",
"target": {
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"function": "sixel_allocator_malloc"
},
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"signature_type": "Function",
"signature_version": "v1"
},
{
"id": "CVE-2020-21049-b7c03e43",
"digest": {
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"source": "https://github.com/saitoha/libsixel/commit/0b1e0b3f7b44233f84e5c9f512f8c90d6bbbe33d",
"target": {
"file": "src/allocator.c"
},
"deprecated": false,
"signature_type": "Line",
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{
"id": "CVE-2020-21049-eca8721e",
"digest": {
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"function_hash": "265876843441913872333024852228689490945"
},
"source": "https://github.com/saitoha/libsixel/commit/0b1e0b3f7b44233f84e5c9f512f8c90d6bbbe33d",
"target": {
"file": "src/allocator.c",
"function": "sixel_allocator_realloc"
},
"deprecated": false,
"signature_type": "Function",
"signature_version": "v1"
}
],
"vanir_signatures_modified": "2026-10-20T13:52:43Z"
}
}
],
"modified": "2026-10-20T13:52:43.155511581Z",
"provider": "osv",
"references": [
"https://github.com/saitoha/libsixel/blob/master/ChangeLog",
"https://github.com/saitoha/libsixel/releases/tag/v1.8.5",
"https://bitbucket.org/netbsd/pkgsrc/commits/970a81d31ec7498e04d09b6b7771cef35f63cd28",
"https://github.com/saitoha/libsixel/commit/0b1e0b3f7b44233f84e5c9f512f8c90d6bbbe33d",
"https://github.com/saitoha/libsixel/issues/74"
],
"provider_metadata": {}
},
"related_cves": [
{
"value": "CVE-2020-21049",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 388336,
"published_at": "2021-09-14T16:15:08.773+00:00"
}