CriticalFix available
lz4 — security advisory
There's a flaw in lz4. An attacker who submits a crafted file to an application linked with lz4 may be able to trigger an integer overflow, leading to calling of memmove() on a negative size argument, causing an out-of-bounds write and/or a crash. The greatest impact of this flaw is to availability, with some potential impact to confidentiality and integrity as well.
- Products
- lz4
- Affected versions
- Not specified
- Fixed versions
- 1.9.2-r1, 1.9.3-r1
- CVEs
- CVE-2021-3520
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 22:05 UTC · Revision 1
Source evidence
There's a flaw in lz4. An attacker who submits a crafted file to an application linked with lz4 may be able to trigger an integer overflow, leading to calling of memmove() on a negative size argument, causing an out-of-bounds write and/or a crash. The greatest impact of this flaw is to availability, with some potential impact to confidentiality and integrity as well.
osv:ALPINE-CVE-2021-3520
lz4
Fixed versions: 1.9.2-r1
lz4
Fixed versions: 1.9.2-r1
lz4
Fixed versions: 1.9.3-r1
lz4
Fixed versions: 1.9.3-r1
lz4
Fixed versions: 1.9.3-r1
lz4
Fixed versions: 1.9.3-r1
lz4
Fixed versions: 1.9.3-r1
lz4
Fixed versions: 1.9.3-r1
lz4
Fixed versions: 1.9.3-r1
lz4
Fixed versions: 1.9.3-r1
lz4
Fixed versions: 1.9.3-r1
lz4
Fixed versions: 1.9.3-r1
lz4
Fixed versions: 1.9.3-r1
Complete source record
{
"id": "7d0b793d8610a9ba3fc204da646c45a55269bd02a05d26cec2e3e1ecc1a23595",
"url": "https://osv.dev/vulnerability/ALPINE-CVE-2021-3520",
"method": "structured",
"payload": {
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"title": "ALPINE-CVE-2021-3520",
"summary": "There's a flaw in lz4. An attacker who submits a crafted file to an application linked with lz4 may be able to trigger an integer overflow, leading to calling of memmove() on a negative size argument, causing an out-of-bounds write and/or a crash. The greatest impact of this flaw is to availability, with some potential impact to confidentiality and integrity as well.",
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{
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],
"severity": "critical",
"structured": {
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"aliases": [
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],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
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"affected": [
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"database_specific": {
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],
"package": {
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"purl": "pkg:apk/alpine/lz4?arch=source",
"ecosystem": "Alpine:v3.14"
},
"database_specific": {
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"ecosystem": "Alpine:v3.16"
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"package": {
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"package": {
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],
"modified": "2026-10-23T17:17:56.196704669Z",
"provider": "osv",
"upstream": [
"CVE-2021-3520"
],
"references": [
"https://security.alpinelinux.org/vuln/CVE-2021-3520"
]
},
"related_cves": [
{
"value": "CVE-2021-3520",
"evidence": "/upstream"
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],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 415480,
"published_at": "2021-06-02T13:15:13.17+00:00"
}