High
Security advisory
Sudo before 1.9.5p2 contains an off-by-one error that can result in a heap-based buffer overflow, which allows privilege escalation to root via "sudoedit -s" and a command-line argument that ends with a single backslash character.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2021-3156
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 08:21 UTC · Revision 1
Source evidence
Sudo before 1.9.5p2 contains an off-by-one error that can result in a heap-based buffer overflow, which allows privilege escalation to root via "sudoedit -s" and a command-line argument that ends with a single backslash character.
osv:CVE-2021-3156
Complete source record
{
"id": "094c70492576a8b8948f775ceecda6d2416e8e9de722039969ad22a7964366fa",
"url": "https://osv.dev/vulnerability/CVE-2021-3156",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "CVE-2021-3156",
"summary": "Sudo before 1.9.5p2 contains an off-by-one error that can result in a heap-based buffer overflow, which allows privilege escalation to root via \"sudoedit -s\" and a command-line argument that ends with a single backslash character.",
"evidence": "osv:CVE-2021-3156",
"products": [],
"severity": "high",
"structured": {
"id": "CVE-2021-3156",
"aliases": [
"CVE-2021-3156"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
}
],
"affected": [
{
"ranges": [
{
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"events": [
{
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{
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},
{
"introduced": "83d1bee918147a57804de77d3e1064a4e323f47e"
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{
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{
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{
"cpe": "cpe:2.3:a:sudo_project:sudo:*:*:*:*:*:*:*:*",
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{
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{
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"source": "CPE_RANGE"
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{
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{
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{
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{
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{
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"SUDO_1_8_17p1",
"SUDO_1_8_17",
"SUDO_1_8_16",
"SUDO_1_8_15",
"SUDO_1_8_14p3",
"SUDO_1_8_14p1",
"SUDO_1_8_14",
"SUDO_1_8_13",
"SUDO_1_8_12",
"SUDO_1_8_11p2",
"SUDO_1_8_11p1",
"SUDO_1_8_11",
"SUDO_1_8_10p3",
"SUDO_1_8_10p2",
"SUDO_1_8_10p1",
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"SUDO_1_8_9p5",
"SUDO_1_8_9p4",
"SUDO_1_8_9p3",
"SUDO_1_8_9p2",
"SUDO_1_8_9p1",
"SUDO_1_8_9",
"SUDO_1_8_8",
"SUDO_1_8_7",
"SUDO_1_8_6p8",
"SUDO_1_8_6p7",
"SUDO_1_8_6p6",
"SUDO_1_8_6p5",
"SUDO_1_8_6p4",
"SUDO_1_8_6p3",
"SUDO_1_8_6p2",
"SUDO_1_8_6p1",
"SUDO_1_8_6",
"SUDO_1_8_5p3",
"SUDO_1_8_5p2",
"SUDO_1_8_5p1",
"SUDO_1_8_5",
"SUDO_1_8_4p5",
"SUDO_1_8_4p4",
"SUDO_1_8_4p3",
"SUDO_1_8_4p2",
"SUDO_1_8_4p1",
"SUDO_1_8_4",
"SUDO_1_8_3",
"SUDO_1_8_2"
],
"database_specific": {
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}
},
{
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"type": "GIT",
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{
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{
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{
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{
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{
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{
"fixed": "1.9.5"
}
],
"source": "CPE_RANGE"
},
{
"cpe": "cpe:2.3:a:sudo_project:sudo:1.9.5:-:*:*:*:*:*:*",
"range": [
{
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{
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}
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{
"cpe": "cpe:2.3:a:sudo_project:sudo:1.9.5:patch1:*:*:*:*:*:*",
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{
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}
]
}
}
],
"versions": [
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"1.9.5-patch1",
"v1.9.4p2",
"SUDO_1_9_4p2",
"v1.9.4p1",
"SUDO_1_9_4p1",
"v1.9.4",
"SUDO_1_9_4",
"v1.9.3p1",
"SUDO_1_9_3p1",
"v1.9.3",
"SUDO_1_9_3",
"v1.9.2",
"SUDO_1_9_2",
"v1.9.1",
"SUDO_1_9_1",
"v1.8.31p2",
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"v1.8.31",
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"SUDO_1_8_21",
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"SUDO_1_8_20p1",
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"SUDO_1_8_13",
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"v1.8.11p2",
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"SUDO_1_8_10p1",
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"SUDO_1_8_8",
"v1.8.7",
"SUDO_1_8_7",
"v1.8.6p8",
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"SUDO_1_8_6p7",
"v1.8.6p6",
"SUDO_1_8_6p6",
"v1.8.6p5",
"SUDO_1_8_6p5",
"v1.8.6p4",
"SUDO_1_8_6p4",
"v1.8.6p3",
"SUDO_1_8_6p3",
"v1.8.6p2",
"SUDO_1_8_6p2",
"v1.8.6p1",
"SUDO_1_8_6p1",
"v1.8.6",
"SUDO_1_8_6",
"v1.8.5p3",
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"SUDO_1_8_5p2",
"v1.8.5p1",
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"SUDO_1_8_5",
"v1.8.4p5",
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"v1.8.4p4",
"SUDO_1_8_4p4",
"v1.8.4p3",
"SUDO_1_8_4p3",
"v1.8.4p2",
"SUDO_1_8_4p2",
"v1.8.4p1",
"SUDO_1_8_4p1",
"v1.8.4",
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"v1.8.3",
"SUDO_1_8_3",
"v1.8.2",
"SUDO_1_8_2"
],
"database_specific": {
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}
}
],
"modified": "2026-10-24T10:31:06.315367815Z",
"provider": "osv",
"references": [
"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-3156",
"https://kc.mcafee.com/corporate/index?page=content&id=SB10348",
"https://lists.debian.org/debian-lts-announce/2021/01/msg00022.html",
"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CALA5FTXIQBRRYUA2ZQNJXB6OQMAXEII/",
"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LHXK6ICO5AYLGFK2TAX5MZKUXTUKWOJY/",
"https://security.gentoo.org/glsa/202101-33",
"https://security.netapp.com/advisory/ntap-20210128-0001/",
"https://security.netapp.com/advisory/ntap-20210128-0002/",
"https://support.apple.com/kb/HT212177",
"https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sudo-privesc-jan2021-qnYQfcM",
"https://www.beyondtrust.com/blog/entry/security-advisory-privilege-management-for-unix-linux-pmul-basic-and-privilege-management-for-mac-pmm-affected-by-sudo-vulnerability",
"https://www.debian.org/security/2021/dsa-4839",
"https://www.kb.cert.org/vuls/id/794544",
"https://www.sudo.ws/stable.html#1.9.5p2",
"https://www.synology.com/security/advisory/Synology_SA_21_02",
"https://www.oracle.com//security-alerts/cpujul2021.html",
"https://www.oracle.com/security-alerts/cpuapr2022.html",
"https://www.oracle.com/security-alerts/cpuoct2021.html",
"https://www.openwall.com/lists/oss-security/2021/01/26/3",
"https://www.vicarius.io/vsociety/posts/sudoedit-pwned-cve-2021-3156"
],
"provider_metadata": {
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{
"cpes": [
"cpe:2.3:a:beyondtrust:privilege_management_for_mac:*:*:*:*:*:*:*:*"
],
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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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},
{
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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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},
{
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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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"cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*"
],
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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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"cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*"
],
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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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"cpe:2.3:a:mcafee:web_gateway:8.2.17:*:*:*:*:*:*:*",
"cpe:2.3:a:mcafee:web_gateway:9.2.8:*:*:*:*:*:*:*"
],
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{
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{
"introduced": "8.2.17"
},
{
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},
{
"introduced": "9.2.8"
},
{
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},
{
"introduced": "10.0.4"
},
{
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}
],
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}
]
},
{
"cpes": [
"cpe:2.3:a:netapp:ontap_tools:9:*:*:*:*:vmware_vsphere:*:*"
],
"vendor_product": "netapp:ontap_tools",
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{
"range": [
{
"introduced": "9"
},
{
"last_affected": "9"
}
],
"source": "CPE_STRING"
}
]
},
{
"cpes": [
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],
"vendor_product": "oracle:micros_compact_workstation_3_firmware",
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{
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{
"introduced": "310"
},
{
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}
],
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}
]
},
{
"cpes": [
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],
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{
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{
"introduced": "210"
},
{
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}
],
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}
]
},
{
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],
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{
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{
"introduced": "5a"
},
{
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}
],
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}
]
},
{
"cpes": [
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],
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{
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{
"introduced": "6.2"
},
{
"last_affected": "6.2"
}
],
"source": "CPE_STRING"
}
]
},
{
"cpes": [
"cpe:2.3:a:synology:diskstation_manager_unified_controller:3.0:*:*:*:*:*:*:*"
],
"vendor_product": "synology:diskstation_manager_unified_controller",
"extracted_events": [
{
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{
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},
{
"last_affected": "3.0"
}
],
"source": "CPE_STRING"
}
]
}
]
}
},
"related_cves": [
{
"value": "CVE-2021-3156",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 440958,
"published_at": "2021-01-26T21:15:12.987+00:00"
}