CVE-2026-98238: net: wwan: t7xx: validate the netif index in t7xx_ccmni_recv_skb()
In the Linux kernel, the following vulnerability has been resolved:
net: wwan: t7xx: validate the netif index in t7xxccmnirecvskb()
The netif index carried in the DPMAIF PIT header is five bits wide, but ccmniinst[] only has room for NICDEVMAX (21) entries. t7xxccmnirecvskb() indexes the array without a bounds check, so indexes 21 to 31 read past it. The out-of-bounds value lands in the callback table that follows the array, which is never NULL, so the existing !ccmni check does not catch it and the driver dereferences whatever sits there as a struct t7xxccmni.
Drop the skb when the index is out of range.
Verified in a QEMU guest with a fault injector setting the netif index to 25: the unpatched driver reads a value past ccmniinst[], which lands in the callback table, and dereferences it far enough to queue the skb. With this check the packet is dropped. Well-formed traffic on index 0 is unaffected.
Changes in v2: none.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Compensating control
In t7xx_ccmni_recv_skb(), validate the five-bit DPMAIF PIT netif index against the ccmni_inst[] bounds and drop the skb when the index is out of range.