CVE-2021-3753

MEDIUMNVD 4.74.7—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 4.7 under NVD CVSS v3. EPSS exploit probability: 0.0%, top 96% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
4.7
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 4.7Exploit: NoneExposed: 0

A fix is available — apply it.

A race problem was seen in the vt_k_ioctl in drivers/tty/vt/vt_ioctl.c in the Linux kernel, which may cause an out of bounds read in vt as the write access to vc_mode is not protected by lock-in vt_ioctl (KDSETMDE). The highest threat from this vulnerability is to data confidentiality.

CVSS v3
4.7
EG Score
4.7(medium)
EPSS
28.9%
KEV
Not listed

Published

February 16, 2022

Last Modified

November 21, 2024

References (8)

Vendor Advisories for CVE-2021-3753(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(9)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulinux-virtual-hwe-16.04-edge (4.15.0.162.151) @ bionic2026-05-26ubuntu
ubuntulinux-headers-5.11.0-1021-raspi (5.11.0-1021.22) @ hirsute2026-05-26ubuntu
ubuntulinux-oem-5.13-tools-5.13.0-1017 (5.13.0-1017.21) @ focal2026-05-26ubuntu
ubuntulinux-oem-tools-host (5.4.0.90.94) @ focal2026-05-26ubuntu
ubuntulinux-image-raspi2-hwe-18.04 (5.4.0.1046.81) @ focal2026-05-26ubuntu
ubuntulinux-image-virtual-lts-xenial (4.4.0.242.210) @ trusty2026-05-26ubuntu
ubuntulinux-tools-oem-20.04-edge (5.10.0.1050.52) @ focal2026-05-26ubuntu
redhatkernel-0:4.18.0-553.el8_102024-05-22redhat
redhatkernel-rt-0:4.18.0-553.rt7.342.el8_102024-05-22redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Additional Vendor Advisories

(9)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 11× in last 7d / 48× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 104 total refreshes for this CVE.

  1. 2026-07-22 14:06 UTCEPSS rescore
  2. 2026-07-21 15:22 UTCEPSS rescore
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  43. 2026-06-12 08:40 UTCOSV refresh
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Frequently asked(5)

What is CVE-2021-3753?
CVE-2021-3753 is a medium vulnerability published on February 16, 2022. A race problem was seen in the vtkioctl in drivers/tty/vt/vtioctl.c in the Linux kernel, which may cause an out of bounds read in vt as the write access to vcmode is not protected by lock-in vt_ioctl (KDSETMDE). The highest threat from this vulnerability is to data confidentiality.
When was CVE-2021-3753 disclosed?
CVE-2021-3753 was first published in the National Vulnerability Database on February 16, 2022, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-3753 actively exploited?
CVE-2021-3753 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 28.9% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-3753?
CVE-2021-3753 has a CVSS v3 base score of 4.7 (NVD).
How do I remediate CVE-2021-3753?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-3753, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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