Headroom underflow in Linux kernel LLC frames on VLAN devices
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
- —
- Confidentiality · integrity · availability
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- Fix status
- Fixed
No CVSS vector from any source. Fix status from CNA.
Summary
The Linux kernel from 2.6.34 is affected. llc_alloc_frame() reserves link-layer headroom based only on the device type, which is too little for stacked Ethernet devices such as VLAN devices. An LLC response on such a device can underflow skb headroom in eth_header().
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: llc: reserve device headroom for allocated frames llc_alloc_frame() reserves link-layer headroom using the device type. This is insufficient for stacked Ethernet devices such as VLAN devices, where vlan_dev_hard_header() pushes a VLAN header before the lower device's Ethernet header. An LLC response on such a device can therefore underflow skb headroom in eth_header(). Use LL_RESERVED_SPACE() to account for the device's actual required headroom while preserving the existing LLC device-type check.
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 | 2.6.34 and later | 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.112, 6.18.55, 7.2.9, 7.3 | Patch available | CNA |
- Linux VendorLinux Affected 2.6.34 and later Fixed in 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.112, 6.18.55, 7.2.9, 7.3 Patch available CNA
Remediation
Update the Linux kernel to a fixed version: 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.112, 6.18.55, 7.2.9 or 7.3, matching the stable branch in use. Kernels in the affected commit ranges are fixed by the upstream commits listed in the record.
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
- Fix · CNA Linux (Linux) Fixed in 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.112, 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-2026-98526
- 2026-10-18 Alias added: GHSA-cxpq-4fh3-6276
- 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
Other 8
- https://git.kernel.org/stable/c/018020f5a48cc86fdd6dc2d380f6c70443ae7639
- https://git.kernel.org/stable/c/3a3f57c4061d9e9cc3bc04205d36ce41ae3406c1
- https://git.kernel.org/stable/c/7c38524b2b2456bd33cb360420da6cbf9cad1b33
- https://git.kernel.org/stable/c/1937222c2511ac91377d39f28106c34734f5f8c6
- https://git.kernel.org/stable/c/16ceac2daa89dd16917bc488ab05b9dd6961a603
- https://git.kernel.org/stable/c/e06f8b6e27cc616d3c587e9784c4a033eb310a16
- https://git.kernel.org/stable/c/3361c93e417384ebf28003e0fb6d5304653d3b05
- https://git.kernel.org/stable/c/72b5b9a28b996e09b8b5b944370c79851bb68f52
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Sources
- CVE-2026-98526 · CVE Program
- CVE-2026-98526 · NVD
- FIRST EPSS
- GHSA-cxpq-4fh3-6276 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-98526 · 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