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CVE-2021-3753

18
FAUCET Score

CVE-2021-3753 is a race condition vulnerability in the Linux kernel's vt_k_ioctl function, specifically affecting drivers/tty/vt/vt_ioctl.c. This flaw can lead to an out-of-bounds read due to unprotected write access to vc_mode during KDSETMDE operations, impacting products like Linux, NetApp, and Red Hat. The vulnerability has a CVSS score of 4.7 (MEDIUM), indicating a local attack vector with high attack complexity and a primary impact on data confidentiality. There is no impact on integrity or availability. Currently, there is no evidence of active exploitation, no public exploit code (Metasploit, Nuclei, ExploitDB), and it is not listed in the CISA KEV catalog. Community discussion and media coverage are minimal, suggesting low public awareness and exploitation.

Impacted Technologies

VendorProductVersion(s)CPE
< 5.15CPE matchmatch criteria
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
7.0CPE matchmatch criteria
cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*
8.0CPE matchmatch criteria
cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*
Range not provided by sourceCPE matchmatch criteria
cpe:2.3:a:netapp:active_iq_unified_manager:-:*:*:*:*:vmware_vsphere:*:*
Range not provided by sourceCPE matchmatch criteria
cpe:2.3:a:netapp:element_software:-:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

4.7MEDIUM

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

Attack Vector
LOCAL
Attack Complexity
HIGH
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
NONE
Availability Impact
NONE
Exploitability Score
1.0
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.36%
Probability of exploitation in next 30 days
EPSS Percentile
29.0%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0036 is in the 78th percentile among its peer group of 1,297 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.1 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.4 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (6)

github_advisorypatch availablevia nvd_reference
View patch
microsoftpatch availablevia msrc
Product: 18780-16820Fixed in: -
microsoftpatch availablevia msrc
Product: cm1 kernel 5.10.102.1-1 on CBL Mariner 1.0Fixed in: -
redhatpatch availablevia nvd_reference
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: kernel-rt-0:4.18.0-553.rt7.342.el8_10
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: kernel-0:4.18.0-553.el8_10
View patch

Vendor Advisories (2)

microsoft2022-Feb/CVE-2021-3753Moderate

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.

Feb 8, 2022
redhatCVE-2021-3753Moderate

kernel: a race out-of-bound read in vt

Sep 1, 2021

References

bugzilla.redhat.com / show_bug.cgi
Issue TrackingPatchThird Party Advisory
github.com / torvalds/linux/commit/2287a51ba822384834dafc1c798453375d1107c7
PatchThird Party Advisory
security.netapp.com / advisory/ntap-20221028-0003
Third Party Advisory
openwall.com / lists/oss-security/2021/09/01/4
ExploitMailing ListPatchThird Party Advisory