CVE-2020-12826: Canonical Ubuntu Linux

Medium severity, CVSS 5.3. EPSS: 0.7% chance of exploitation in the next 30 days.

A signal access-control issue was discovered in the Linux kernel before 5.6.5, aka CID-7395ea4e65c2. Because exec_id in include/linux/sched.h is only 32 bits, an integer overflow can interfere with a do_notify_parent protection mechanism. A child process can send an arbitrary signal to a parent process in a different security domain. Exploitation limitations include the amount of elapsed time before an integer overflow occurs, and the lack of scenarios where signals to a parent process present a substantial operational threat.

Affected products

• Canonical Ubuntu Linux: version 20.04 only
• Linux Linux Kernel: before 5.6.5 (fixed in 5.6.5)
• Red Hat Enterprise Linux: version 5.0 only; version 6.0 only; version 7.0 only; version 8.0 only
• Red Hat Enterprise Mrg: version 2.0 only

Published 2020-05-12. Last modified 2026-06-17.