Security readout for executives and security teams
CVE-2021-3493 is a Ubuntu Linux kernel flaw that lets a local low-privileged attacker gain higher privileges. It is not a remote internet bug by itself, but it matters when attackers already have a shell, compromised account, or workload foothold. CISA lists it in KEV, so treat it as exploited and operationally important. Exposure is most likely on Ubuntu systems running the listed affected kernel lines, especially multi-user servers, developer hosts, container-adjacent environments, or systems where untrusted code can run locally. The provided evidence does not support treating non-Ubuntu kernels as affected unless vendor guidance says so. Patch this as a high-priority Linux fleet issue, especially on Ubuntu systems with local user access or workload execution. KEV listing raises urgency because exploitation is known, but the local-access requirement keeps it below a standalone remote compromise scenario. Mitigation focus: Apply Ubuntu kernel updates referenced by USN-4917-1.; Prioritize internet-facing servers where local code execution is plausible.; Review CISA KEV deadlines and internal remediation SLAs..
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-270: Exact CWE lookup
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Open ATT&CK lookupCVE-2021-3493 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 8.8 (3.1)
- Known Exploited
- Yes
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/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:C/C:H/I:H/A:H26Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
8.8HighVector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://ubuntu.com/security/notices/USN-4917-1CVE reference · x_refsource_MISC
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7c03e2cda4a584cadc398e8f6641ca9988a39d52CVE reference · x_refsource_MISC
- https://www.openwall.com/lists/oss-security/2021/04/16/1CVE reference · x_refsource_MISC
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-3493CVE 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.
Privilege Context Switching Error
Privilege Context Switching Error represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.