CVE-2026-53286: Linux IDPF Double-Free and Use-After-Free Vulnerability

Technical summary

The vulnerability exists in error-handling paths within idpf_plug_vport_aux_dev() and idpf_plug_core_aux_dev() functions. When auxiliary_device_add() fails, control flows to the err_aux_dev_add label, which calls auxiliary_device_uninit(). This invokes put_device(), triggering a release callback that frees the iadev structure. The code then falls through to err_aux_dev_init, which attempts to read adev->id from the now-freed iadev for ida_free(), followed by a kfree() call—resulting in a double-free condition and use-after-free access. The fix involves freeing the IDA slot and clearing the back-pointer before uninit while adev remains valid, then returning immediately. A related use-after-free in the unplug path was addressed in commit 65637c3a1811, but both probe error paths were missed.

Business impact

Exploitation of this vulnerability could cause kernel panics, disrupting services relying on IDPF networking capabilities. While local-only access is required, any unprivileged user with local shell access can trigger this condition. Affected deployments—particularly cloud infrastructure, data centers, and high-performance computing environments using Intel DPK-based networking—face potential denial-of-service risk. In worst-case scenarios, privilege escalation may be possible through kernel heap exploitation techniques.

Affected systems

The vulnerability affects Linux kernel systems running with IDPF driver support. This includes distributions and kernels that have integrated Intel's IDPF driver for advanced packet processing. Specific kernel version ranges and distribution impacts should be verified against vendor-issued advisories and security bulletins.

Exploitability

Exploitability is moderate. The flaw requires local access and unprivileged user privileges (as indicated by CVSS vector PR:L). An attacker must be able to execute code on the affected system and trigger the auxiliary device initialization error path—typically achievable through user-space tools or drivers that interact with IDPF. The vulnerability is not remotely exploitable. The logical error in the cleanup sequence makes exploitation straightforward for a local attacker familiar with kernel debugging.

Remediation

Apply kernel patches addressing the double-free and use-after-free in both probe error paths. The fix restructures the error-handling sequence to release IDA slots and clear back-pointers before calling auxiliary_device_uninit(), ensuring memory safety. Organizations should prioritize patching systems exposing IDPF driver functionality to unprivileged local users, particularly in cloud and virtualized environments where user isolation is critical.

Patch guidance

Consult your Linux distribution's security advisories and kernel maintainer repositories for patched versions. Verify that applied patches address both idpf_plug_vport_aux_dev() and idpf_plug_core_aux_dev() error paths, as the historical fix (commit 65637c3a1811) addressed only the unplug path. Test patches in non-production environments first to ensure compatibility with your IDPF driver configuration and networking stack.

Detection guidance

Monitor kernel logs and system metrics for signs of heap corruption, double-free warnings, and kernel panics occurring during IDPF auxiliary device operations. Kernel Address Sanitizer (KASAN) and other debug features can help detect use-after-free and double-free conditions during testing. Watch for processes attempting to trigger device initialization failures through ioctl or sysfs interactions. Intrusion detection systems should flag unusual patterns of device initialization attempts followed by system restarts.

Why prioritize this

Despite being classified as HIGH (CVSS 7.8), this vulnerability carries moderate practical risk in well-segmented environments due to its requirement for local user access. However, prioritize remediation in: (1) multi-tenant cloud platforms where user isolation is security-critical, (2) edge computing and IoT deployments using IDPF for performance-critical networking, and (3) development and testing environments where unprivileged user access is common. Systems with strict local access controls can afford a longer remediation window.

Risk score, explained

The CVSS 3.1 score of 7.8 (HIGH) reflects the combination of local attack vector (AV:L), low attack complexity (AC:L), and low privileges required (PR:L), balanced against high impact on confidentiality, integrity, and availability (C:H/I:H/A:H). The score appropriately penalizes the local-only nature of the attack but recognizes that a successful exploit could fully compromise system security and stability. The vulnerability is not yet tracked in CISA's Known Exploited Vulnerabilities list.

Frequently asked questions