CVE-2021-29155

Published: 20 April 2021

An issue was discovered in the Linux kernel through 5.11.x. kernel/bpf/verifier.c performs undesirable out-of-bounds speculation on pointer arithmetic, leading to side-channel attacks that defeat Spectre mitigations and obtain sensitive information from kernel memory. Specifically, for sequences of pointer arithmetic operations, the pointer modification performed by the first operation is not correctly accounted for when restricting subsequent operations.

From the Ubuntu security team

Piotr Krysiuk and Benedict Schlueter discovered that the eBPF implementation in the Linux kernel performed out of bounds speculation on pointer arithmetic. A local attacker could use this to expose sensitive information.

Priority

Medium

CVSS 3 base score: 5.5

Status

References

• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-29155
• https://www.openwall.com/lists/oss-security/2021/04/18/4
• https://www.kernel.org
• https://ubuntu.com/security/notices/USN-4977-1
• https://ubuntu.com/security/notices/USN-4983-1
• https://ubuntu.com/security/notices/USN-4999-1
• NVD
• Launchpad
• Debian

Bugs