kernel: /sys/kernel/debug/acpi/custom_method can bypass module restrictions
Published Jun 21, 2012
3.6
LOWCVSS 2.0
EPSS 0.93%
Description
drivers/acpi/debugfs.c in the Linux kernel before 3.0 allows local users to modify arbitrary kernel memory locations by leveraging root privileges to write to the /sys/kernel/debug/acpi/custom_method file. NOTE: this vulnerability exists because of an incomplete fix for CVE-2010-4347.
Affected products
No data.
- ≤ 2.6.9
- 2.6.9
- 2.6.9
- 2.6.9
- 2.6.9
No data.
Red Hat Enterprise MRG 2
kernel-rt-0:2.6.33.9-rt31.75.el6rt
Fixed · RHSA-2011:1253
Red Hat Enterprise Linux 4
kernel
Not affected
Red Hat Enterprise Linux 5
kernel
Not affected
Red Hat Enterprise Linux 6
kernel
Not affected
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise MRG 2 | kernel-rt-0:2.6.33.9-rt31.75.el6rt | Fixed | RHSA-2011:1253 |
| Red Hat Enterprise Linux 4 | kernel | Not affected | n/a |
| Red Hat Enterprise Linux 5 | kernel | Not affected | n/a |
| Red Hat Enterprise Linux 6 | kernel | Not affected | n/a |
No package ranges for this CVE.
Remediation
Red Hat statement
The version of Linux kernel as shipped with Red Hat Enterprise Linux 4, 5, and 6 as they did not include upstream commit a1a541d8 and a25ee920 that introduced the problem. This has been addressed in Red Hat Enterprise MRG via https://rhn.redhat.com/errata/RHSA-2011-1253.html. Notes: This requires debugfs to be mounted on a local system in order to have access to the custom_method file. Debugfs is not mounted by default. You need to run "mount -t debugfs nodev /sys/kernel/debug" as root first.
Metrics
No CVSS v4.0 score for this CVE.
No CVSS v3.1 score for this CVE.
No CVSS v3.0 score for this CVE.
AV:L/AC:L/Au:N/C:N/I:P/A:P
This CVE is not in the KEV list.
No CISA SSVC assessment for this CVE yet.
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 1, 2026.
Score over time
2022–2026- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Percentile over time
- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Table of values (11 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 0.93% (0.00928) | 59.13th | v5 (v2026.06.15) |
| Jun 15, 2026 | 0.93% (0.00928) | 55.73th | v5 (v2026.06.15) |
| Mar 17, 2025 | 0.12% (0.00124) | 29.16th | v4 (v2025.03.14) |
| Dec 12, 2024 | 0.04% (0.00042) | 5.07th | v3 (v2023.03.01) |
| Mar 7, 2023 | 0.04% (0.00042) | 5.63th | v3 (v2023.03.01) |
| Mar 6, 2023 | 0.95% (0.00950) | 32.28th | v2 (v2022.01.01) |
| Feb 13, 2023 | 0.95% (0.00950) | 31.86th | v2 (v2022.01.01) |
| Feb 3, 2023 | 1.03% (0.01034) | 40.96th | v2 (v2022.01.01) |
| Sep 10, 2022 | 0.95% (0.00950) | 30.63th | v2 (v2022.01.01) |
| Apr 1, 2022 | 0.95% (0.00950) | 28.61th | v2 (v2022.01.01) |
| Feb 4, 2022 | 0.95% (0.00950) | 13.46th | v2 (v2022.01.01) |
References (8)
- http://ftp.osuosl.org/pub/linux/kernel/v3.0/ChangeLog-3.0 x_refsource_CONFIRM
- http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git%3Ba=commit%3Bh=526b4af47f44148c9d665e57723ed9f86634c6e3 x_refsource_CONFIRM
- http://www.openwall.com/lists/oss-security/2011/02/25/5 mailing-listx_refsource_MLIST
- https://access.redhat.com/security/cve/CVE-2011-1021 Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=680841 x_refsource_CONFIRMIssue Tracking
- https://github.com/torvalds/linux/commit/526b4af47f44148c9d665e57723ed9f86634c6e3 x_refsource_CONFIRMExploitPatch
- https://nvd.nist.gov/vuln/detail/CVE-2011-1021
- https://www.cve.org/CVERecord?id=CVE-2011-1021
| Link | Providers | Tags |
|---|---|---|
| http://ftp.osuosl.org/pub/linux/kernel/v3.0/ChangeLog-3.0 | x_refsource_CONFIRM | |
| http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git%3Ba=commit%3Bh=526b4af47f44148c9d665e57723ed9f86634c6e3 | x_refsource_CONFIRM | |
| http://www.openwall.com/lists/oss-security/2011/02/25/5 | mailing-listx_refsource_MLIST | |
| https://access.redhat.com/security/cve/CVE-2011-1021 | Vendor Advisory | |
| https://bugzilla.redhat.com/show_bug.cgi?id=680841 | x_refsource_CONFIRMIssue Tracking | |
| https://github.com/torvalds/linux/commit/526b4af47f44148c9d665e57723ed9f86634c6e3 | x_refsource_CONFIRMExploitPatch | |
| https://nvd.nist.gov/vuln/detail/CVE-2011-1021 | ||
| https://www.cve.org/CVERecord?id=CVE-2011-1021 |
Change history (0)
No recorded changes yet.