Unchecked copy in Linux kernel MHI WWAN MBIM driver leaks heap memory
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
- Partial Red Hat: 4 without a fix
No CVSS vector from any source. Fix status from CNA and Red Hat.
Summary
The Linux kernel mhi_wwan_mbim WWAN driver ignores the return value of skb_copy_bits() when it copies each datagram out of a received NTB. A modem can supply a datagram offset and length that point outside the received buffer, so the copy fails and the uninitialized buffer is passed to the network stack, leaking kernel heap memory.
Written with Claude Haiku 5.5 from the sources below · 2026-10-30
Description from the CNA
In the Linux kernel, the following vulnerability has been resolved: net: wwan: mhi_wwan_mbim: check skb_copy_bits() return value mhi_mbim_rx() ignores the return value of skb_copy_bits() when it copies each datagram out of the NTB. The datagram offset and length come from the DPE, which is only checked to lie within the NTB itself, so a modem can point a datagram outside the received skb. The copy then fails and the freshly allocated skbn is passed to netif_rx() with its uninitialized contents still in place, leaking kernel heap memory into the network stack. Free the skb and account an error when the copy fails. Verified in a QEMU guest with a fault injector pointing a DPE outside the received NTB: the copy fails, and the unpatched driver hands the uninitialized skbn to the network stack (observed as "unknown protocol" on bytes that were never written). With this check the failed datagram is dropped and counted as an rx error. Changes in v2: factor the free-and-count sequence out into mhi_mbim_rx_drop(), shared with the unknown-protocol path, as suggested by Loic Poulain.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
Remediation
Update the Linux kernel to a fixed version: 5.15.222, 6.1.189, 6.6.158, 6.12.112, 6.18.54, 7.2.8 or 7.3, or a kernel that includes the fixing commits in the affected list. Red Hat lists no available fix for Red Hat Enterprise Linux 10, 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 · 2026-10-30
- Fix · CNA Linux (Linux) Fixed in 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: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet: Fix deferred |
Not affected: 5 products
- 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
Timeline
- 2026-10-06 Threatist record created from CVE-2026-98236
- 2026-10-06 Alias added: GHSA-f277-f268-9h2q
- 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
- 2026-10-30 Affected versions changed · Red Hat
- 2026-11-01 Affected versions changed · Red Hat
References
Other 7
- https://git.kernel.org/stable/c/650af68435eaee783824457d2ef78cc5c03c1e88
- https://git.kernel.org/stable/c/350fd3125ee26b5243935fd9e2b4d162ffba430a
- https://git.kernel.org/stable/c/dd136f1fdd1059f3bc25ede3a8def8f0ee151ce7
- https://git.kernel.org/stable/c/298659c3677bf622afa9d77549cb4a967f9541e9
- https://git.kernel.org/stable/c/02eba5f36d20283f144f75d47f0354a85e4f78f0
- https://git.kernel.org/stable/c/7e98216e9da08b79e07a514d2a4f7646f8c9ccb9
- https://git.kernel.org/stable/c/31550d585589fde1ae95bf7f7a8188b2d2fdf1c7
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Sources
- CVE-2026-98236 · CVE Program
- CVE-2026-98236 · NVD
- FIRST EPSS
- GHSA-f277-f268-9h2q · GitHub Advisory Database · CC BY 4.0
- CVE-2026-98236 · 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