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Vulnerability record · CVE-2021-21781 · published 18 August 2021

CVE-2021-21781: Linux kernel use of uninitialized resource vulnerability

Linux · Linux Kernel

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

3.3 CVSS 3.1 Low EPSS 0.50% · top 59.9% CWE-908 · Use of uninitialized resource
3.3CVSS 3.1 base score, v2 2.1
0.50%EPSS exploitation probability, 30 days
NoNot in CISA KEV
4Affected product versions listed by NVD
4References, 2 tagged exploit
17 Jun 2026Last modified by NVD

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

Affected products

4 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://talosintelligence.com/vulnerability_reports/TALOS-2021-1243 ExploitThird Party Advisory
https://www.oracle.com/security-alerts/cpujul2022.html PatchThird Party Advisory
https://talosintelligence.com/vulnerability_reports/TALOS-2021-1243 ExploitThird Party Advisory
https://www.oracle.com/security-alerts/cpujul2022.html PatchThird Party Advisory

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Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2021-21781), CISA KEV, FIRST EPSS (scores of 2026-09-28). This page is refreshed as NVD updates the record.