Security readout for executives and security teams
CVE-2021-3156 is a Sudo flaw that can let a local user gain root privileges. It affects Sudo versions before 1.9.5p2. Because CISA KEV marks it as known exploited, organizations should treat vulnerable Unix-like hosts and products that ship Sudo as urgent remediation targets. Exposure is most likely on Linux, Unix, macOS, and network or storage products that include Sudo before 1.9.5p2. Local account access is required. Vendor advisories in the bundle include Debian, Gentoo, Fedora, Cisco, Apple, Oracle, and NetApp, but each environment needs package-level verification. Treat this as an urgent privilege-escalation issue. It does not provide initial remote access by itself, but it can turn any local foothold into root control on vulnerable systems. KEV status raises remediation priority above routine high-severity patching. Mitigation focus: Upgrade Sudo to 1.9.5p2 or the vendor-fixed package release.; Prioritize internet-facing servers where local footholds may become root compromise.; Apply vendor advisories for appliances and managed products that bundle Sudo..
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
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ATT&CK lookup starting points
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CWE-193: Exact CWE lookup
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Open ATT&CK lookupPrivilege behavior lookup
The CVE wording references privilege impact, so privilege escalation and authorization behavior review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-3156 mapping review
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Open ATT&CK lookup- Severity
- High
- CVSS
- 7.8 (3.1)
- Known Exploited
- Yes
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CISA KEV status
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H1.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.8HighVector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- [debian-lts-announce] 20210126 [SECURITY] [DLA 2534-1] sudo security updateCVE reference · mailing-list
- GLSA-202101-33CVE reference · vendor-advisory
- DSA-4839CVE reference · vendor-advisory
- FEDORA-2021-2cb63d912aCVE reference · vendor-advisory
- FEDORA-2021-8840cbdccdCVE reference · vendor-advisory
- 20210129 Sudo Privilege Escalation Vulnerability Affecting Cisco Products: January 2021CVE reference · vendor-advisory
- VU#794544CVE reference · third-party-advisory
- https://www.oracle.com//security-alerts/cpujul2021.htmlCVE reference
- https://www.sudo.ws/stable.html#1.9.5p2CVE reference
- https://www.openwall.com/lists/oss-security/2021/01/26/3CVE reference
- https://security.netapp.com/advisory/ntap-20210128-0002/CVE reference
- https://security.netapp.com/advisory/ntap-20210128-0001/CVE reference
- https://support.apple.com/kb/HT212177CVE reference
- https://kc.mcafee.com/corporate/index?page=content&id=SB10348CVE reference
- https://www.beyondtrust.com/blog/entry/security-advisory-privilege-management-for-unix-linux-pmul-basic-and-privilege-management-for-mac-pmm-affected-by-sudo-vulnerabilityCVE reference
- https://www.synology.com/security/advisory/Synology_SA_21_02CVE reference
- https://www.oracle.com/security-alerts/cpuoct2021.htmlCVE reference
- https://www.oracle.com/security-alerts/cpuapr2022.htmlCVE reference
- https://www.vicarius.io/vsociety/posts/sudoedit-pwned-cve-2021-3156CVE reference
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-3156CVE reference · government-resource
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Off-by-one Error
Off-by-one Error represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.