CVE-2021-20320: Infoleak
A flaw was found in s390 eBPF JIT in bpfjitinsn in arch/s390/net/bpfjitcomp.c in the Linux kernel . In this flaw, a local attacker with special user privilege can circumvent the verifier and may lead to a confidentiality problem.
Uncovered three miscompilation issues in the s390 eBPF JIT. They can be used by an unprivileged local user to circumvent the verifier and gain root privileges. This series fixes all 3; no new tests are required since Johan's tests will be integrated upstream.
- 2 fixes are for initial s390x eBPF JIT compiler backend implementation, v4.1+ - 1 fix v5.5+
https://lore.kernel.org/bpf/20210902185229.1840281-1-johan.almbladh@anyfinetworks.com/
Other sources
A flaw was found in s390 eBPF JIT in bpfjitinsn in arch/s390/net/bpfjitcomp.c in the Linux kernel. In this flaw, a local attacker with special user privilege can circumvent the verifier and may lead to a confidentiality problem.
— MITRE
Affected Software
Remediation
Event History
Frequently Asked Questions
What is the severity of CVE-2021-20320?
CVE-2021-20320 is classified as a medium severity vulnerability that can lead to potential confidentiality issues.
How do I fix CVE-2021-20320?
To fix CVE-2021-20320, update the Linux kernel to version 5.15 or higher.
Who is affected by CVE-2021-20320?
CVE-2021-20320 affects users of the Linux kernel versions prior to 5.15, particularly on s390 architecture.
What types of attacks can exploit CVE-2021-20320?
Exploitation of CVE-2021-20320 may allow local attackers with special user privileges to bypass security mechanisms.
Is CVE-2021-20320 a widespread vulnerability?
CVE-2021-20320 impacts various Linux distributions including Fedora and Red Hat Enterprise Linux, making it relevant for many users.