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Fencer Intel
medium 5.5

CVE-2011-4621 json

The Linux kernel before 2.6.37 does not properly implement a certain clock-update optimization, which allows local users to cause a denial…

published 2012-05-17 14 y ago modified 2026-06-16 4 mo ago also EUVD-2011-4544

cvss
5.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 38%
public exploits
0
none known

Summary

The Linux kernel before 2.6.37 does not properly implement a certain clock-update optimization, which allows local users to cause a denial of service (system hang) via an application that executes code in a loop.

Patch / fix

  • linux linux_kernel 2.6.37
  • kernel RHEL 6 2.6.32-220.2.1.el6
  • perf RHEL 6 2.6.32-220.2.1.el6
  • python-perf RHEL 6 2.6.32-220.2.1.el6
  • kernel-kdump RHEL 6 2.6.32-220.2.1.el6
  • kernel-firmware RHEL 6 2.6.32-220.2.1.el6
  • kernel-bootwrapper RHEL 6 2.6.32-220.2.1.el6
  • kernel-debuginfo-common-i686 RHEL 6 2.6.32-220.2.1.el6
  • kernel-debuginfo-common-ppc64 RHEL 6 2.6.32-220.2.1.el6

red hat advisories RHSA-2011:1849

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2011-4621 updated cvss 4.7

kernel: tight loop and no preemption can cause system stall

  • Red Hat Enterprise Linux Desktop (v. 6) perf 2.6.32-220.2.1.el6, kernel 2.6.32-220.2.1.el6, kernel-firmware 2.6.32-220.2.1.el6, kernel-debuginfo-common-i686 2.6.32-220.2.1.el6, kernel-debuginfo-common-x86_64 2.6.32-220.2.1.el6 Red Hat Enterprise Linux Desktop Optional (v. 6) kernel 2.6.32-220.2.1.el6, python-perf 2.6.32-220.2.1.el6, kernel-debuginfo-common-i686 2.6.32-220.2.1.el6, kernel-debuginfo-common-x86_64 2.6.32-220.2.1.el6 Red Hat Enterprise Linux HPC Node (v. 6) perf 2.6.32-220.2.1.el6, kernel 2.6.32-220.2.1.el6, kernel-firmware 2.6.32-220.2.1.el6, kernel-debuginfo-common-x86_64 2.6.32-220.2.1.el6 Red Hat Enterprise Linux HPC Node Optional (v. 6) kernel 2.6.32-220.2.1.el6, python-perf 2.6.32-220.2.1.el6, kernel-debuginfo-common-x86_64 2.6.32-220.2.1.el6 Red Hat Enterprise Linux Server (v. 6) perf 2.6.32-220.2.1.el6, kernel 2.6.32-220.2.1.el6, kernel-kdump 2.6.32-220.2.1.el6, kernel-firmware 2.6.32-220.2.1.el6, kernel-bootwrapper 2.6.32-220.2.1.el6, kernel-debuginfo-common-i686 2.6.32-220.2.1.el6, +3 more Red Hat Enterprise Linux Server Optional (v. 6) kernel 2.6.32-220.2.1.el6, python-perf 2.6.32-220.2.1.el6, kernel-debuginfo-common-i686 2.6.32-220.2.1.el6, kernel-debuginfo-common-ppc64 2.6.32-220.2.1.el6, kernel-debuginfo-common-s390x 2.6.32-220.2.1.el6, kernel-debuginfo-common-x86_64 2.6.32-220.2.1.el6
    +2 more products
    Red Hat Enterprise Linux Workstation (v. 6) perf 2.6.32-220.2.1.el6, kernel 2.6.32-220.2.1.el6, kernel-firmware 2.6.32-220.2.1.el6, kernel-debuginfo-common-i686 2.6.32-220.2.1.el6, kernel-debuginfo-common-x86_64 2.6.32-220.2.1.el6 Red Hat Enterprise Linux Workstation Optional (v. 6) kernel 2.6.32-220.2.1.el6, python-perf 2.6.32-220.2.1.el6, kernel-debuginfo-common-i686 2.6.32-220.2.1.el6, kernel-debuginfo-common-x86_64 2.6.32-220.2.1.el6
    fixed: vendor fix RHSA-2011:1849
  • Red Hat Enterprise Linux 4 kernel Red Hat Enterprise Linux 5 kernel Red Hat Enterprise MRG 2 kernel-rt, mrg-rt-release, kernel-rt-trace, kernel-rt-vanilla, kernel-rt-firmware
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.44% chance of exploitation in the next 30 days, higher than 38% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • openwall.com http://www.openwall.com/lists/oss-security/2011/12/21/6 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 4.9 AV:L/AC:L/Au:N/C:N/I:N/A:C

Classification

Weakness
  • CWE-835 Loop with Unreachable Exit Condition
Technology feeds

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.