Zero ring size rounding in Linux kernel fbnic Ethernet driver
Key facts
- Attack vector
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- Privileges required
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- User interaction
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- Attack complexity
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- Impact type
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- Confidentiality · integrity · availability
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- Fix status
- Fixed
No CVSS vector from any source. Fix status from CNA.
Summary
The Linux kernel fbnic Ethernet driver from 6.15 is affected. The driver rounds ring sizes up to a power of two using a function that is undefined for zero, and ethtool can pass a zero ring size to the driver. An attacker who can set ring sizes through ethtool can trigger this, and the fix leaves zero unchanged so the minimum-size check rejects it.
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
Description from the CNA
In the Linux kernel, the following vulnerability has been resolved: eth: fbnic: Avoid rounding zero ring sizes roundup_pow_of_two() is undefined for zero. ethtool permits a zero ring size to reach the driver, where the minimum-size check should reject it. Leave zero unchanged while rounding nonzero ring sizes. The minimum-size check then rejects zero deterministically without changing the established behavior for other values.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
Remediation
Upgrade the Linux kernel to 6.18.55, 7.2.9 or 7.3, which contain the fix.
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
- Fix · CNA Linux (Linux) Fixed in 6.18.55, 7.2.9, 7.3
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
Not affected: 7 products
- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat OpenShift Container Platform 4
- Red Hat OpenShift Container Platform 5
Timeline
- 2026-10-18 Threatist record created from CVE-2026-98585
- 2026-10-18 Alias added: GHSA-pmrp-mw94-3ww9
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-10-20 Affected versions changed · Red Hat
- 2026-10-20 CVSS score added · Red Hat
- 2026-11-06 Affected versions changed · Red Hat
References
More Linux vulnerabilities
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- TI-2021-02452 Incorrect authorization in Ubuntu linux kernel KEVCVSS 3.1HIGH 8.8
- TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
- TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
- 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-2026-98585 · CVE Program
- CVE-2026-98585 · NVD
- FIRST EPSS
- GHSA-pmrp-mw94-3ww9 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-98585 · Red Hat security data · CC BY 4.0
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