CVE-2026-89509

RDMA/ionic: Embed counter driver data in rdma_counter allocation

Published Sep 11, 2026 CVSS 3.1 · 4.1 Medium EPSS < 1% KEV · Not listed

Description

In the Linux kernel, the following vulnerability has been resolved:

RDMA/ionic: Embed counter driver data in rdma_counter allocation

Commit 7e53b31acc7f ("RDMA/core: Create and destroy rdma_counter using
rdma_zalloc_drv_obj()") requires drivers implementing counter ops to
embed struct rdma_counter in a driver-specific struct, register its size
via INIT_RDMA_OBJ_SIZE, and provide a counter_init callback.

The ionic driver was merged without this adaptation, causing a NULL
pointer dereference in alloc_and_bind() since rdma_zalloc_drv_obj()
allocates zero bytes when size_rdma_counter is unset.

Consolidate struct ionic_counter into a new struct ionic_rdma_counter
that embeds struct rdma_counter, replace the xarray with a lightweight
ida for ID allocation, and add the required counter_init and
INIT_RDMA_OBJ_SIZE declarations.

Analysis

Technical impact

The ionic RDMA driver fails to register the size of its embedded rdma_counter structure during initialization, causing rdma_zalloc_drv_obj to allocate zero bytes. When alloc_and_bind attempts to use the counter, it dereferences a NULL pointer and the kernel panics. The weakness is a NULL pointer dereference (CWE-476) and the ultimate effect is a system-wide crash, resulting in a denial of service.

Affected Systems

All Linux kernel releases that ship the ionic RDMA driver without the application of commit 7e53b31 (which registers INIT_RDMA_OBJ_SIZE) are affected. This includes any distribution kernel where the ionic RDMA module is loaded. If RDMA is disabled or the driver is not present the vulnerability does not manifest.

Risk and Exploitability

The CVSS score of 4.1 indicates low severity. The EPSS score of < 1% implies a very low likelihood of exploitation, and the vulnerability is not listed in CISA KEV. Based on the description, it is inferred that an attacker would need the ability to load or enable the ionic RDMA driver, which typically requires root privileges or the use of signed modules. The likely attack vector is local privilege or kernel module load; upon successful exploitation, a kernel crash occurs, causing a reboot or shutdown.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

Linux

unaffected

Version	Status	Constraints
`ea4c399642b85dc30f44d90ee805c6a18fa03062`	affected	< c98197ee3cd28288da13dc9881bb9e74daa7cbbc
`ea4c399642b85dc30f44d90ee805c6a18fa03062`	affected	< 08b8630b557828aedb1d9ef0a6e2ec421f334ee2
`ea4c399642b85dc30f44d90ee805c6a18fa03062`	affected	< cf3ebd89e754015625fee90aa938f6bc79a2c974

Linux

affected

Version	Status	Constraints
`6.18`	affected	—
`0`	unaffected	< 6.18
`6.18.51`	unaffected	≤ 6.18.*
`7.2.4`	unaffected	≤ 7.2.*
`7.3`	unaffected	≤ *

No data.

Vendor Product Versions

Linux

Linux Kernel

Version	Status	Scheme	Platform
`[ea4c399642b85dc30f44d90ee805c6a18fa03062,c98197ee3cd28288da13dc9881bb9e74daa7cbbc)`	affected	code_commit	—
`[ea4c399642b85dc30f44d90ee805c6a18fa03062,08b8630b557828aedb1d9ef0a6e2ec421f334ee2)`	affected	code_commit	—
`[ea4c399642b85dc30f44d90ee805c6a18fa03062,cf3ebd89e754015625fee90aa938f6bc79a2c974)`	affected	code_commit	—

Linux

Linux Kernel

Version	Status	Scheme	Platform
`6.18`	affected	semver	—
`[0,6.18)`	unaffected	semver	—
`[6.18.51,6.19.0)`	unaffected	semver	—
`[7.2.4,7.3.0)`	unaffected	semver	—
`[7.3-rc1,*]`	unaffected	generic	—

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

Upgrade the kernel to a version containing commit 7e53b31 or later so the ionic RDMA driver correctly registers the counter size and performs initialization.
If a kernel update cannot be applied immediately, blacklist or otherwise prevent the ionic RDMA driver from loading by adding it to a module blacklist configuration file.
Enforce strict module‑signing policies and limit module loading to trusted users; monitor kernel logs for RDMA or ionic driver activity to detect accidental or malicious loading attempts.

Generated by OpenCVE AI on September 15, 2026 at 22:23 UTC.

Tracking

Advisories

Source	ID	Title
Ubuntu USN	USN-9019-1	Linux kernel (Azure) vulnerabilities
Ubuntu USN	USN-9020-1	Linux kernel vulnerabilities

Metrics

No CVSS v4.0

Attack Vector Local

Attack Complexity High

Privileges Required High

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.206% probability within 30 days)

Key SSVC decision points have not yet been added.

References

Link	Providers
https://git.kernel.org/stable/c/08b8630b557828aedb1d9ef0a6e2ec421f334ee2
https://git.kernel.org/stable/c/c98197ee3cd28288da13dc9881bb9e74daa7cbbc
https://git.kernel.org/stable/c/cf3ebd89e754015625fee90aa938f6bc79a2c974
https://nvd.nist.gov/vuln/detail/CVE-2026-89509
https://www.cve.org/CVERecord?id=CVE-2026-89509

History

Sep 12, 2026 12:15 AM Weaknesses updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
Weaknesses		CWE-476
References		https://nvd.nist.gov/vuln/detail/CVE-2026-89509 https://www.cve.org/CVERecord?id=CVE-2026-89509
Metrics	threat_severity `None`	cvssV3_1 `{'score': 4.1, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H'}` threat_severity `Important`

Sep 11, 2026 11:45 PM Description updated. Title updated. First appearance in the feed. Affected versions updated. Affected vendors updated. Added references View changes

Type	Values Removed	Values Added
Description		In the Linux kernel, the following vulnerability has been resolved: RDMA/ionic: Embed counter driver data in rdma_counter allocation Commit 7e53b31acc7f ("RDMA/core: Create and destroy rdma_counter using rdma_zalloc_drv_obj()") requires drivers implementing counter ops to embed struct rdma_counter in a driver-specific struct, register its size via INIT_RDMA_OBJ_SIZE, and provide a counter_init callback. The ionic driver was merged without this adaptation, causing a NULL pointer dereference in alloc_and_bind() since rdma_zalloc_drv_obj() allocates zero bytes when size_rdma_counter is unset. Consolidate struct ionic_counter into a new struct ionic_rdma_counter that embeds struct rdma_counter, replace the xarray with a lightweight ida for ID allocation, and add the required counter_init and INIT_RDMA_OBJ_SIZE declarations.
Title		RDMA/ionic: Embed counter driver data in rdma_counter allocation
First Time appeared		Linux Linux linux Kernel
CPEs		cpe:2.3:o:linux:linux_kernel::::::::
Vendors & Products		Linux Linux linux Kernel
References		https://git.kernel.org/stable/c/08b8630b557828aedb1d9ef0a6e2ec421f334ee2 https://git.kernel.org/stable/c/c98197ee3cd28288da13dc9881bb9e74daa7cbbc https://git.kernel.org/stable/c/cf3ebd89e754015625fee90aa938f6bc79a2c974