CVE-2021-21781

3.3 LOW 0.5% exploit odds Fix listed

What it is

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

At a glance

Exploitability: Can be exploited locally on the machine with a low-privilege account. Limited direct impact.
Exploit odds: 0.5% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2021-08-18 15:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-06-17 03:36 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.5% in the next 30 days (EPSS).
Severity: 3.3 LOW (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2021-08-18 15:15 UTC
Last modified: 2026-06-17 03:36 UTC
Exploit probability: 0.5% · EPSS, next 30 days
Weakness: CWE-908
Record status: Modified

Affected

Linux Kernel 5.4.54
Linux Kernel 5.4.66
Oracle Communications Cloud Native Core Binding Support Function 22.1.3
Oracle Communications Cloud Native Core Network Exposure Function 22.1.1
Oracle Communications Cloud Native Core Policy 22.2.0

Attack profile CVSS 3.1 · 3.3

Attack vector: Local
Complexity: Low
Privileges needed: Low
User interaction: None
Scope: Unchanged
Confidentiality: Low
Integrity: None
Availability: None

Raw vector

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

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2021-21781.md and follow it. Check whether this project is affected by CVE-2021-21781. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

· More options · Status badge

Download Square Reddit

Fix and advisories

References

NVD record · CVE.org record