CVE-2021-20219: linux linux_kernel Incorrect Comparison
Vulnerability summary
CVE-2021-20219 is a medium (CVSS 5.5) Incorrect Comparison vulnerability in linux linux_kernel. EPSS estimates a 0.40% chance of exploitation in the next 30 days, higher than 33.1% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 8 · Related 8Timeline
- 23-03-2021PublishedVulnerability first disclosed.
- 03-08-2024Last modifiedVulnerability information updated.
Description
A denial of service vulnerability was found in n_tty_receive_char_special in drivers/tty/n_tty.c of the Linux kernel. In this flaw a local attacker with a normal user privilege could delay the loop (due to a changing ldata->read_head, and a missing sanity check) and cause a threat to the system availability.
CVSS metrics
3 scores · 2 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated5.5MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
0.40%
Chance of exploitation in the next 30 days
Percentile
33%
Versus all other CVEs
30-day change
No change 0.00 pp
From 0.40% on 22-09-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Ubuntu18 products
- linux-awsAll versions (No fix recorded)
- linux-aws-5.0All versions (No fix recorded)
- linux-aws-5.3All versions (No fix recorded)
- linux-azureAll versions (No fix recorded)
- linux-azure-5.3All versions (No fix recorded)
Linux1 product
- linux_kernel< 4.18
2 vendors · 19 products