Vulnerability in Linux Kernel

CVE-2011-4080

The sysrq_sysctl_handler function in kernel/sysctl.c in the Linux kernel before 2.6.39 does not require the CAP_SYS_ADMIN capability to modify the dmesg_restrict value, which allows local users to bypass intended access restrictions and read the kernel ring buffer by leveraging root privileges, as demonstrated by a root user in a Linux Containers (aka LXC) environment.

Published 2012-05-24 · last modified 2026-06-16.

CVSS v2 metric

CVSS v2 base score 4.0 (Medium). Vector: AV:L/AC:H/Au:N/C:C/I:N/A:N. This CVE predates CVSS v3 and has no v3 score from NVD.

EPSS exploit prediction

EPSS: 0.003 (26.2th percentile), scored 2026-10-02.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 26th percentile — 26.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000

Affected products

Linux Kernel

Weakness classification (CWE)

CWE-264

References

github.com/torvalds/linux/commit/bfdc0b497faa82a0ba2f9dddcf109231dd519fcc (Patch, Third Party Advisory)
www.openwall.com/lists/oss-security/2011/10/26/10 (mailing-list, Mailing List, Third Party Advisory)
ftp.osuosl.org/pub/linux/kernel/v2.6/ChangeLog-2.6.39 (Broken Link)
git.kernel.org/