Bug 2482164 (CVE-2026-45940) - CVE-2026-45940 kernel: net: stmmac: fix oops when split header is enabled
Summary: CVE-2026-45940 kernel: net: stmmac: fix oops when split header is enabled
Keywords:
Status: NEW
Alias: CVE-2026-45940
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
unspecified
unspecified
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-05-27 15:14 UTC by OSIDB Bzimport
Modified: 2026-05-28 00:23 UTC (History)
2 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
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Description OSIDB Bzimport 2026-05-27 15:14:20 UTC
In the Linux kernel, the following vulnerability has been resolved:

net: stmmac: fix oops when split header is enabled

For GMAC4, when split header is enabled, in some rare cases, the
hardware does not fill buf2 of the first descriptor with payload.
Thus we cannot assume buf2 is always fully filled if it is not
the last descriptor. Otherwise, the length of buf2 of the second
descriptor will be calculated wrong and cause an oops:

Unable to handle kernel paging request at virtual address ffff00019246bfc0
...
x2 : 0000000000000040 x1 : ffff00019246bfc0 x0 : ffff00009246c000
Call trace:
 dcache_inval_poc+0x28/0x58 (P)
 dma_direct_sync_single_for_cpu+0x38/0x6c
 __dma_sync_single_for_cpu+0x34/0x6c
 stmmac_napi_poll_rx+0x8f0/0xb60
 __napi_poll.constprop.0+0x30/0x144
 net_rx_action+0x160/0x274
 handle_softirqs+0x1b8/0x1fc
...

To fix this, the PL bit-field in RDES3 register is used for all
descriptors, whether it is the last descriptor or not.


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