Out-of-bounds write in the Linux kernel RDMA/siw driver
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Partial Red Hat: 4 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.
Summary
The Linux kernel RDMA/siw driver is affected in the ranges from 5.4.220 before 5.5, from 5.10.150 before 5.10.271, from 5.15.75 before 5.15.222, from 5.19.17 before 5.20, from 6.0.3 before 6.1, and from 6.1 onward until the branch fixes listed below. When a TCP stream splits an extended DDP/RDMAP header across callbacks, siw_get_hdr() copies too few bytes on the later callback, so the copy writes past the header end and corrupts the receive state. A later callback then uses a negative offset, causing an out-of-bounds write. A remote unauthenticated attacker can trigger this over the network without user interaction.
Written with Claude Haiku 5.5 from the sources below · 2026-11-05
Description from the CNA
In the Linux kernel, the following vulnerability has been resolved: RDMA/siw: Bound fragmented header copies by the remaining length siw_get_hdr() can receive an extended DDP/RDMAP header across more than one TCP callback. The first callback may receive most of the header, while the next one still limits the copy to hdrlen - MIN_DDP_HDR instead of the number of missing bytes. This makes the destination move past the end of the header and overwrite the receive state, including fpdu_part_rcvd. A later callback can then use a negative fpdu_part_rcvd value as a copy offset, which creates an OOB write. Use the number of header bytes already received when calculating the next copy length.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 5.10.150 to before 5.10.271; 5.15.75 to before 5.15.222; 5.4.220 to before 5.5; 5.19.17 to before 5.20; 6.0.3 to before 6.1 | 5.10.271, 5.15.222, 5.5, 5.20, 6.1 | Patch available | CNA |
| Linux | Linux | 6.1 and later | 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.112, 6.18.54, 7.2.8, 7.3 | Patch available | CNA |
- Linux VendorLinux Affected 5.10.150 to before 5.10.271; 5.15.75 to before 5.15.222; 5.4.220 to before 5.5; 5.19.17 to before 5.20; 6.0.3 to before 6.1 Fixed in 5.10.271, 5.15.222, 5.5, 5.20, 6.1 Patch available CNA
- Linux VendorLinux Affected 6.1 and later Fixed in 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.112, 6.18.54, 7.2.8, 7.3 Patch available CNA
Remediation
Linux kernel fixes are available in 5.5, 5.10.271, 5.15.222, 5.20, 6.1, 6.1.189, 6.6.158, 6.12.112, 6.18.54, 7.2.8 and 7.3. Red Hat lists no available fix plan for Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 and Red Hat OpenShift Container Platform 5.
Written with Claude Haiku 5.5 from the sources below · 2026-11-05
- Fix · CNA Linux (Linux) Fixed in 5.10.271, 5.15.222, 5.5, 5.20, 6.1
- Fix · CNA Linux (Linux) Fixed in 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.112, 6.18.54, 7.2.8, 7.3
Vendor assessments
Red Hat
Red Hat rating: Important. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 8 | Affected | No fix yet |
| Red Hat Enterprise Linux 9 | Affected | No fix yet |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet |
Not affected: 4 products
- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat OpenShift Container Platform 4
Timeline
- 2026-10-06 Threatist record created from CVE-2026-98323
- 2026-10-06 Alias added: GHSA-6mmc-6x3m-rgjh
- 2026-10-07 CVSS score added · CNA
- 2026-10-07 Priority changed: LOW → MEDIUM
- 2026-10-10 Affected versions changed · Red Hat
- 2026-10-10 CVSS score added · Red Hat
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-11-05 Affected versions changed · Red Hat
References
Other 8
- https://git.kernel.org/stable/c/2c6fbcf4bfac0b2b186acc8d91154c0fa24468a7
- https://git.kernel.org/stable/c/af9f5b474a260ad23ffb9793d716a5e3bbce3b48
- https://git.kernel.org/stable/c/262dcd809723723ed8a4e05437ec7e9c21a8f17e
- https://git.kernel.org/stable/c/eb4d7a946970469b3ab0c762432bf161d5b0836c
- https://git.kernel.org/stable/c/8628f8ebf41669302513fb3f0bf0eba38b226742
- https://git.kernel.org/stable/c/b72dcfb9bf1f0f0147cda03dc59e4002a315067f
- https://git.kernel.org/stable/c/e6bdfdf3bcb02d0d626a45e8c98b7e63d2fddf9d
- https://git.kernel.org/stable/c/9ff797e516dbc1ecb73701ec4c24055712d44411
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- TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
Sources
- CVE-2026-98323 · CVE Program
- CVE-2026-98323 · NVD
- FIRST EPSS
- GHSA-6mmc-6x3m-rgjh · GitHub Advisory Database · CC BY 4.0
- CVE-2026-98323 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences