CVE-2021-20265 Denial of service in kernel

What is CVE-2021-20265?

CVE-2021-20265 is a medium-severity denial of service vulnerability in Linux kernel, published on 10 Mar 2021. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

A flaw was found in the way memory resources were freed in the unix_stream_recvmsg function in the Linux kernel when a signal was pending. This flaw allows an unprivileged local user to crash the system by exhausting available memory. The highest threat from this vulnerability is to system availability.

Weakness: CWE-401, CWE-400

Which versions are affected by CVE-2021-20265?

It affects 2 products.

Products include Linux kernel, Oracle Tekelec Platform Distribution.

How do I fix CVE-2021-20265?

Apply the vendor's patch.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2021-20265 being exploited?

There is no known exploitation of CVE-2021-20265 in the wild and no public exploit code.

Other vulnerabilities in Linux kernel

• CVE-2026-53266 Linux Kernel Out-of-Bounds Write Exploited High 8.8
• CVE-2013-6282 Linux Kernel Improper Input Validation Exploited High 8.8
• CVE-2022-0185 Linux Kernel Heap-Based Buffer Overflow Exploited High 8.4
• CVE-2013-2094 Linux Kernel Privilege Escalation Exploited High 8.4
• CVE-2026-53362 Linux Kernel Unspecified Exploited High 7.8

All Linux kernel vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as DEBIAN-CVE-2021-20265, GHSA-7j7j-cjf4-3c2x, UBUNTU-CVE-2021-20265.