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.

A flaw was found in the Linux kernel's `stmmac` Ethernet driver. When split header functionality is enabled for GMAC4, the hardware may not fully populate a buffer in the first descriptor. This can lead to an incorrect calculation of buffer length in subsequent descriptors, resulting in a kernel panic (oops) and causing a Denial of Service (DoS) to the system. This issue can be triggered under specific network conditions.

Red Hat Enterprise Linux 10 Not affected kernel Red Hat Enterprise Linux 6 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel-rt Red Hat Enterprise Linux 8 Not affected kernel Red Hat Enterprise Linux 8 Not affected kernel-rt Red Hat Enterprise Linux 9 Fix deferred kernel Red Hat Enterprise Linux 9 Fix deferred kernel-rt https://www.cve.org/CVERecord?id=CVE-2026-45940 https://nvd.nist.gov/vuln/detail/CVE-2026-45940 https://lore.kernel.org/linux-cve-announce/2026052729-CVE-2026-45940-4159@gregkh/T