CVE-2021-3493

Exploitation

Exploited in the wild. Listed in the CISA Known Exploited Vulnerabilities catalog on 2022-10-20. Federal remediation due 2022-11-10.

SSVC decision

• ExploitationactiveCISA reports credible evidence of active exploitation.
• AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
• Technical ImpacttotalSuccessful exploitation gives total control of the vulnerable component.

CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.

EPSS probability

49.17% probability of exploitation activity in the next 30 days.

EPSS percentile

Ranks above 98.8% of scored records. A rank, not a probability.

NVD base score

7.8 (CVSS v3.x), scored by the NVD independently of the CNA.

NVD CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

NVD analysis status

Analyzed. NVD last modified this record on 2026-06-17.

Red Hat severity

Moderate. Red Hat's rating for its own products, not a CVSS rating.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

Published

2021-04-17 04:20Z5 YR AGO

Last updated

2025-10-21 23:25Z10 MO AGO

Reserved

2021-04-12

Assigning CNA

canonical

Record state

PUBLISHED

Severity

High (CVSS 8.8)

CNA CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Weaknesses

• CWE-270Privilege Context Switching ErrorBase
• CWE-863Incorrect AuthorizationClass
• CWE-552Files or Directories Accessible to External PartiesBase

Data version

5.1

Document digest

b5c5aaa7c44be296a39252b07a083760bb6e9c0928a18e395b2b89ec1edcf465

• ubuntu.comhttps://ubuntu.com/security/notices/USN-4917-1x_refsource_MISC
• git.kernel.orghttps://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7c03e2cda4a584cadc398e8f6641ca9988a39d52x_refsource_MISC
• www.openwall.comhttps://www.openwall.com/lists/oss-security/2021/04/16/1x_refsource_MISC
• packetstormsecurity.comhttp://packetstormsecurity.com/files/162434/Kernel-Live-Patch-Security-Notice-LSN-0076-1.htmlx_refsource_MISC
• packetstormsecurity.comhttp://packetstormsecurity.com/files/162866/Ubuntu-OverlayFS-Local-Privilege-Escalation.htmlx_refsource_MISC
• packetstormsecurity.comhttp://packetstormsecurity.com/files/165151/Ubuntu-Overlayfs-Local-Privilege-Escalation.htmlx_refsource_MISC
• www.cisa.govhttps://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-3493government-resource