Medium
hashcat — security advisory
hashcat contains a heap-based buffer overflow (out-of-bounds write) in the outfile_write() function in src/outfile.c. When assembling output into a fixed-size buffer (HCBUFSIZ_LARGE, ~16 MB), the function sequentially appends the username, separator, hash, and plaintext via memcpy without validating that the accumulated length stays within the buffer capacity. When run with --username --show against a crafted hash file containing an oversized username that nearly fills the buffer, the total assembled output exceeds the buffer, causing a heap buffer overflow that can corrupt memory and crash the process.
- Products
- hashcat
- Affected versions
- 3.60-1, 4.0.1-1, 5.1.0+ds1-1, 5.1.0+ds1-2, 6.1.1+ds1-1, 6.2.5+ds1-2, 6.2.6+ds1-1, 6.2.6+ds1-1build1, 6.2.6+ds1-1build2, 6.2.6+ds2-1, 7.1.2+ds1-3, 7.1.2+ds1-4
- Fixed versions
- Not specified
- CVEs
- CVE-2026-68768
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 02:50 UTC · Revision 1
Source evidence
hashcat contains a heap-based buffer overflow (out-of-bounds write) in the outfile_write() function in src/outfile.c. When assembling output into a fixed-size buffer (HCBUFSIZ_LARGE, ~16 MB), the function sequentially appends the username, separator, hash, and plaintext via memcpy without validating that the accumulated length stays within the buffer capacity. When run with --username --show against a crafted hash file containing an oversized username that nearly fills the buffer, the total assembled output exceeds the buffer, causing a heap buffer overflow that can corrupt memory and crash the process.
osv:UBUNTU-CVE-2026-68768
hashcat
Fixed versions: Not specified
hashcat
Fixed versions: Not specified
hashcat
Fixed versions: Not specified
hashcat
Fixed versions: Not specified
hashcat
Fixed versions: Not specified
hashcat
Fixed versions: Not specified
Complete source record
{
"id": "c275f84b07558c2be5d0ac682668fafa03883bfbf38f6690ee2d05ffb24ed277",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-68768",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "UBUNTU-CVE-2026-68768",
"summary": "hashcat contains a heap-based buffer overflow (out-of-bounds write) in the outfile_write() function in src/outfile.c. When assembling output into a fixed-size buffer (HCBUFSIZ_LARGE, ~16 MB), the function sequentially appends the username, separator, hash, and plaintext via memcpy without validating that the accumulated length stays within the buffer capacity. When run with --username --show against a crafted hash file containing an oversized username that nearly fills the buffer, the total assembled output exceeds the buffer, causing a heap buffer overflow that can corrupt memory and crash the process.",
"evidence": "osv:UBUNTU-CVE-2026-68768",
"products": [
{
"name": {
"value": "hashcat",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "3.60-1",
"evidence": "/affected/0/versions"
},
{
"value": "4.0.1-1",
"evidence": "/affected/0/versions"
}
]
},
{
"name": {
"value": "hashcat",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
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"affected_versions": [
{
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"evidence": "/affected/1/versions"
},
{
"value": "5.1.0+ds1-2",
"evidence": "/affected/1/versions"
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{
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"affected_versions": [
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"evidence": "/affected/2/versions"
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{
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"evidence": "/affected/2/versions"
}
]
},
{
"name": {
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"evidence": "/affected/3/package/name"
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"prerequisites": [],
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"affected_versions": [
{
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"evidence": "/affected/3/versions"
},
{
"value": "6.2.6+ds1-1build1",
"evidence": "/affected/3/versions"
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{
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"evidence": "/affected/3/versions"
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{
"name": {
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"evidence": "/affected/4/package/name"
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"affected_versions": [
{
"value": "7.1.2+ds1-3",
"evidence": "/affected/4/versions"
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{
"value": "7.1.2+ds1-4",
"evidence": "/affected/4/versions"
}
]
},
{
"name": {
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"evidence": "/affected/5/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "6.2.6+ds2-1",
"evidence": "/affected/5/versions"
},
{
"value": "7.1.2+ds1-3",
"evidence": "/affected/5/versions"
}
]
}
],
"severity": "medium",
"structured": {
"id": "UBUNTU-CVE-2026-68768",
"aliases": [
"UBUNTU-CVE-2026-68768"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:H"
},
{
"type": "CVSS_V4",
"score": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N"
},
{
"type": "Ubuntu",
"score": "medium"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "hashcat",
"purl": "pkg:deb/ubuntu/hashcat?arch=source&distro=bionic",
"ecosystem": "Ubuntu:18.04:LTS"
},
"versions": [
"3.60-1",
"4.0.1-1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-68768.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "hashcat",
"binary_version": "4.0.1-1"
},
{
"binary_name": "hashcat-data",
"binary_version": "4.0.1-1"
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]
}
},
{
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"package": {
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"ecosystem": "Ubuntu:20.04:LTS"
},
"versions": [
"5.1.0+ds1-1",
"5.1.0+ds1-2"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-68768.json"
},
"ecosystem_specific": {
"binaries": [
{
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{
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}
},
{
"ranges": [
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}
],
"package": {
"name": "hashcat",
"purl": "pkg:deb/ubuntu/hashcat?arch=source&distro=jammy",
"ecosystem": "Ubuntu:22.04:LTS"
},
"versions": [
"6.1.1+ds1-1",
"6.2.5+ds1-2"
],
"database_specific": {
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},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "hashcat",
"binary_version": "6.2.5+ds1-2"
},
{
"binary_name": "hashcat-data",
"binary_version": "6.2.5+ds1-2"
}
]
}
},
{
"ranges": [
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"package": {
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"ecosystem": "Ubuntu:24.04:LTS"
},
"versions": [
"6.2.6+ds1-1",
"6.2.6+ds1-1build1",
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},
"ecosystem_specific": {
"binaries": [
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}
},
{
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"ecosystem": "Ubuntu:26.10"
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"versions": [
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"7.1.2+ds1-4"
],
"database_specific": {
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},
"ecosystem_specific": {
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},
{
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"ecosystem": "Ubuntu:26.04:LTS"
},
"versions": [
"6.2.6+ds2-1",
"7.1.2+ds1-3"
],
"database_specific": {
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},
"ecosystem_specific": {
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{
"binary_name": "hashcat",
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},
{
"binary_name": "hashcat-data",
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}
]
}
}
],
"modified": "2026-10-17T12:59:23.628945850Z",
"provider": "osv",
"upstream": [
"CVE-2026-68768"
],
"references": [
"https://ubuntu.com/security/CVE-2026-68768",
"https://www.cve.org/CVERecord?id=CVE-2026-68768",
"https://github.com/hashcat/hashcat/issues/4740",
"https://github.com/hashcat/hashcat/pull/4754"
]
},
"related_cves": [
{
"value": "CVE-2026-68768",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/1/score"
},
"source_id": "core-osv",
"document_id": 359638,
"published_at": "2026-08-22T15:16:00+00:00"
}