4

CVE-2021-21781: linux linux_kernel Use of Uninitialized Resource

Modified
AliasesUBUNTU-CVE-2021-21781DEBIAN-CVE-2021-21781
Published 18-08-2021Last modified 03-08-2024

Vulnerability summary

CVE-2021-21781 is a medium (CVSS 4.0) Use of Uninitialized Resource vulnerability in linux linux_kernel. EPSS estimates a 0.50% chance of exploitation in the next 30 days, higher than 42.6% of scored vulnerabilities. 1 public exploit is recorded.

Priority
Routine

Not severe (CVSS 4, local access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
4.0/10
010
Medium · v3.0 (CVE.org)
EPSS score
0.50%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits1reference

Advisory lineage

Upstream 0 · Downstream 14 · Related 8
DLA-2713-1MGASA-2021-0099MGASA-2021-0100MGASA-2021-0101MGASA-2021-0102OPENSUSE-SU-2021:1142-1

Timeline

  1. 18-08-2021
    PublishedVulnerability first disclosed.
  2. 03-08-2024
    Last modifiedVulnerability information updated.

Description

An information disclosure vulnerability exists in the ARM SIGPAGE functionality of Linux Kernel v5.4.66 and v5.4.54. The latest version (5.11-rc4) seems to still be vulnerable. A userland application can read the contents of the sigpage, which can leak kernel memory contents. An attacker can read a process’s memory at a specific offset to trigger this vulnerability. This was fixed in kernel releases: 4.14.222 4.19.177 5.4.99 5.10.17 5.11

CVSS metrics

7 scores · 4 sources · 3 versions

EPSS trend

Probability

0.50%

Chance of exploitation in the next 30 days

Percentile

43%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.50% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

1 found
  • referenceUnverified

    Exploit Reference (talosintelligence.com)

    Maturity: unknown

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: local access, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

Ubuntu48 products
  • linuxAll versions (No fix recorded) | < 4.15.0-143.147 | < 5.4.0-71.79
  • linux-awsAll versions (No fix recorded) | < 4.15.0-1102.109 | < 5.4.0-1043.45
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.3All versions (No fix recorded)
  • linux-aws-5.4< 5.4.0-1043.45~18.04.1
Oracle3 products
Debian1 product
  • linux< 5.10.19-1
Linux1 product

4 vendors · 53 products

References

6 links