CVE-2023-54257
NoneCVSS
—
EPSS
0.6%
Published
Dec 30, 2025
CISA due date
—
Cloudanix analysis
A bug in the Linux kernel's handling of certain network chips could cause sudden and lasting loss of network connectivity on affected hardware.
- Exploitation
- Adjacent Network
- Attacker needs
- None
- Complexity
- High
- Impact
- Denial Of Service
- Component
- OS kernel
- Class
- Memory Corruption
- Remediation
- Upgrade
- Effort
- Medium
- Patch risk
- Low
What it actually does
Memory corruption in the macb Ethernet driver RX path under extended buffer descriptor mode, manifesting as attempts to free unallocated DMA memory or exceeding overlapping cacheline DMA mappings.
Why it matters to the business
Sudden permanent loss of networking and storage (MMC) functionality on affected Linux devices; low exploitability but high sensitivity to kernel changes and debug options; no known active campaigns or ransomware use.
How an attack unfolds
An attacker triggers specific RX DMA conditions in the macb driver (e.g., via crafted network traffic or device interaction) that expose the descriptor handling flaw, resulting in DMA API violations and system instability; no named threat actors or public exploits observed.
How to fix it
Update the Linux kernel to a version containing commit dd7a49a3eaf723a01b2fdf153f98450a82b0b0fe; rebuild and deploy the fixed kernel across all affected systems.
How to confirm the fix worked
Confirm the running kernel contains commit dd7a49a3eaf723a01b2fdf153f98450a82b0b0fe; reproduce prior DMA debug warnings under CONFIG_DMA_API_DEBUG=y to verify absence after upgrade.
Typical attack path
- Identify systems running vulnerable macb driver in extended buffer mode
- Send or induce network traffic that exercises the RX DMA path
- Trigger DMA unmap or mapping overlap conditions leading to corruption warnings
- Cause networking stack failure and potential MMC disruption
How to detect it
Search kernel logs for DMA-API warnings referencing macb, check_unmap, add_dma_entry, or gem_rx during network receive processing; examine dmesg or syslog for device address and size mismatch entries.
What your security team should do
- Prioritize kernel upgrade on all devices using the macb driver
- Monitor EPSS trend for any increase beyond current low score
- Enable DMA API debugging in test environments to validate the fix
- Review device trees and driver configurations for extended buffer descriptor usage
The record
In the Linux kernel, the following vulnerability has been resolved: net: macb: fix a memory corruption in extended buffer descriptor mode For quite some time we were chasing a bug which looked like a sudden permanent failure of networking and mmc on some of our devices. The bug was very sensitive to any software changes and even more to any kernel debug options. Finally we got a setup where the problem was reproducible with CONFIG_DMA_API_DEBUG=y and it revealed the issue with the rx dma: [ 16.992082] ------------[ cut here ]------------ [ 16.996779] DMA-API: macb ff0b0000.ethernet: device driver tries to free DMA memory it has not allocated [device address=0x0000000875e3e244] [size=1536 bytes] [ 17.011049] WARNING: CPU: 0 PID: 85 at kernel/dma/debug.c:1011 check_unmap+0x6a0/0x900 [ 17.018977] Modules linked in: xxxxx [ 17.038823] CPU: 0 PID: 85 Comm: irq/55-8000f000 Not tainted 5.4.0 #28 [ 17.045345] Hardware name: xxxxx [ 17.049528] pstate: 60000005 (nZCv daif -PAN -UAO) [ 17.054322] pc : check_unmap+0x6a0/0x900 [ 17.058243] lr : check_unmap+0x6a0/0x900 [ 17.062163] sp : ffffffc010003c40 [ 17.065470] x29: ffffffc010003c40 x28: 000000004000c03c [ 17.070783] x27: ffffffc010da7048 x26: ffffff8878e38800 [ 17.076095] x25: ffffff8879d22810 x24: ffffffc010003cc8 [ 17.081407] x23: 0000000000000000 x22: ffffffc010a08750 [ 17.086719] x21: ffffff8878e3c7c0 x20: ffffffc010acb000 [ 17.092032] x19: 0000000875e3e244 x18: 0000000000000010 [ 17.097343] x17: 0000000000000000 x16: 0000000000000000 [ 17.102647] x15: ffffff8879e4a988 x14: 0720072007200720 [ 17.107959] x13: 0720072007200720 x12: 0720072007200720 [ 17.113261] x11: 0720072007200720 x10: 0720072007200720 [ 17.118565] x9 : 0720072007200720 x8 : 000000000000022d [ 17.123869] x7 : 0000000000000015 x6 : 0000000000000098 [ 17.129173] x5 : 0000000000000000 x4 : 0000000000000000 [ 17.134475] x3 : 00000000ffffffff x2 : ffffffc010a1d370 [ 17.139778] x1 : b420c9d75d27bb00 x0 : 0000000000000000 [ 17.145082] Call trace: [ 17.147524] check_unmap+0x6a0/0x900 [ 17.151091] debug_dma_unmap_page+0x88/0x90 [ 17.155266] gem_rx+0x114/0x2f0 [ 17.158396] macb_poll+0x58/0x100 [ 17.161705] net_rx_action+0x118/0x400 [ 17.165445] __do_softirq+0x138/0x36c [ 17.169100] irq_exit+0x98/0xc0 [ 17.172234] __handle_domain_irq+0x64/0xc0 [ 17.176320] gic_handle_irq+0x5c/0xc0 [ 17.179974] el1_irq+0xb8/0x140 [ 17.183109] xiic_process+0x5c/0xe30 [ 17.186677] irq_thread_fn+0x28/0x90 [ 17.190244] irq_thread+0x208/0x2a0 [ 17.193724] kthread+0x130/0x140 [ 17.196945] ret_from_fork+0x10/0x20 [ 17.200510] ---[ end trace 7240980785f81d6f ]--- [ 237.021490] ------------[ cut here ]------------ [ 237.026129] DMA-API: exceeded 7 overlapping mappings of cacheline 0x0000000021d79e7b [ 237.033886] WARNING: CPU: 0 PID: 0 at kernel/dma/debug.c:499 add_dma_entry+0x214/0x240 [ 237.041802] Modules linked in: xxxxx [ 237.061637] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G W 5.4.0 #28 [ 237.068941] Hardware name: xxxxx [ 237.073116] pstate: 80000085 (Nzcv daIf -PAN -UAO) [ 237.077900] pc : add_dma_entry+0x214/0x240 [ 237.081986] lr : add_dma_entry+0x214/0x240 [ 237.086072] sp : ffffffc010003c30 [ 237.089379] x29: ffffffc010003c30 x28: ffffff8878a0be00 [ 237.094683] x27: 0000000000000180 x26: ffffff8878e387c0 [ 237.099987] x25: 0000000000000002 x24: 0000000000000000 [ 237.105290] x23: 000000000000003b x22: ffffffc010a0fa00 [ 237.110594] x21: 0000000021d79e7b x20: ffffffc010abe600 [ 237.115897] x19: 00000000ffffffef x18: 0000000000000010 [ 237.121201] x17: 0000000000000000 x16: 0000000000000000 [ 237.126504] x15: ffffffc010a0fdc8 x14: 0720072007200720 [ 237.131807] x13: 0720072007200720 x12: 0720072007200720 [ 237.137111] x11: 0720072007200720 x10: 0720072007200720 [ 237.142415] x9 : 0720072007200720 x8 : 0000000000000259 [ 237.147718] x7 : 0000000000000001 x6 : 0000000000000000 [ 237.15302 ---truncated---
Affected packages
| Ecosystem | Package | Introduced | Fixed |
|---|---|---|---|
| Linux | Kernel | 4.13.0 | 4.14.313 |
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