CVE-2023-2269 Overview
CVE-2023-2269 is a denial of service vulnerability in the Linux Kernel Device Mapper-Multipathing sub-component. The flaw exists in the table_clear function in drivers/md/dm-ioctl.c. A recursive locking scenario can trigger a deadlock condition, halting kernel execution paths that depend on the affected lock. The vulnerability is classified under [CWE-413] (Improper Resource Locking) and [CWE-667] (Improper Locking). Exploitation requires local access with high privileges, limiting the practical attack surface. Successful exploitation produces an availability impact without compromising confidentiality or integrity.
Critical Impact
A local privileged user can trigger a kernel deadlock through the device mapper ioctl interface, resulting in denial of service on the affected system.
Affected Products
- Linux Kernel version 6.2
- Fedora 36, 37, and 38
- Debian Linux 10.0, 11.0, and 12.0
- NetApp H-Series firmware (H300S, H500S, H700S, H410S, H410C)
Discovery Timeline
- 2023-04-25 - CVE-2023-2269 published to NVD
- 2023-07 - Debian LTS advisory published
- 2023-09-29 - NetApp Security Advisory NTAP-20230929-0004 released
- 2023-10 - Additional Debian LTS advisory published
- 2024-11-21 - Last updated in NVD database
Technical Details for CVE-2023-2269
Vulnerability Analysis
The vulnerability resides in the table_clear function within drivers/md/dm-ioctl.c, part of the Linux Kernel Device Mapper subsystem. Device Mapper provides the kernel framework used by Logical Volume Manager (LVM), dm-crypt, and multipath storage. The table_clear operation is invoked through the device mapper ioctl interface when userspace requests clearing of an inactive mapping table.
Under specific call sequences, the function can attempt to acquire a lock it already holds, producing a classic recursive locking scenario. Because the kernel lock primitive involved is non-recursive, the second acquisition blocks indefinitely. The result is a deadlock that stalls any thread waiting on the affected lock, including legitimate device mapper operations.
Root Cause
The root cause is improper locking discipline in the dm-ioctl code path. The control flow leading to table_clear does not consistently track whether the relevant lock is already held before reacquiring it. This violates the locking contract enforced by the kernel synchronization primitive and corresponds to the CWE-667 weakness pattern.
Attack Vector
Exploitation requires local access with high privileges, typically CAP_SYS_ADMIN, to issue ioctl calls against the /dev/mapper/control interface. An attacker with sufficient privileges crafts a sequence of device mapper ioctl operations that funnels execution into the recursive locking path inside table_clear. The vulnerability cannot be triggered remotely and cannot be exploited from an unprivileged user context, which is reflected in its limited attack surface.
The vulnerability mechanism is described in the upstream Linux Kernel Mailing List Discussion. No public proof-of-concept exploit is available, and the issue is not listed in the CISA Known Exploited Vulnerabilities catalog.
Detection Methods for CVE-2023-2269
Indicators of Compromise
- Kernel soft lockup or hung task warnings referencing device mapper threads or table_clear in stack traces.
- Unresponsive dmsetup commands or stalled LVM operations on affected hosts.
- Processes blocked in uninterruptible sleep (D state) waiting on device mapper locks.
Detection Strategies
- Inventory Linux hosts running kernel 6.2, Debian 10/11/12, or Fedora 36/37/38 and correlate with patch status from vendor advisories.
- Monitor /var/log/kern.log and dmesg for INFO: task ... blocked messages tied to dm-ioctl call paths.
- Audit which local accounts hold CAP_SYS_ADMIN or root on hosts exposing the device mapper interface, as these are the only viable abuse vectors.
Monitoring Recommendations
- Enable kernel hung task detection (kernel.hung_task_timeout_secs) and forward warnings to centralized logging.
- Track ioctl activity against /dev/mapper/control from non-administrative service accounts.
- Alert on sustained increases in D-state processes that coincide with device mapper utilities such as dmsetup or multipath.
How to Mitigate CVE-2023-2269
Immediate Actions Required
- Apply the kernel update referenced in Debian Security Advisory DSA-5448 and Debian Security Advisory DSA-5480 on affected Debian systems.
- Update Fedora hosts using the packages from the Fedora Package Announcement.
- Apply NetApp firmware updates per NetApp Security Advisory NTAP-20230929-0004 on H-Series appliances.
- Restrict CAP_SYS_ADMIN and root access to the minimum set of administrators required for storage management.
Patch Information
The upstream fix is tracked in the Linux Kernel Mailing List Discussion and integrated into stable kernel updates distributed by Debian, Fedora, and downstream vendors. Debian users should upgrade linux packages to the versions listed in DSA-5448 or DSA-5480. Fedora users should consume the updated kernel builds announced for Fedora 36, 37, and 38. NetApp customers must follow vendor guidance for H300S, H500S, H700S, H410S, and H410C firmware.
Workarounds
- Limit invocation of device mapper ioctl operations to trusted administrative workflows until patches are applied.
- Use Linux Security Modules such as SELinux or AppArmor to constrain which processes may open /dev/mapper/control.
- Reduce the number of accounts holding CAP_SYS_ADMIN to lower the local attack surface on shared multi-tenant hosts.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
