CVE-2026-93830— net: stmmac: xgmac2: disable RBUE in default RX interrupt mask
Quick assessment
Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.
在 Linux 内核中，已解决以下漏洞： net: stmmac: xgmac2：在默认接收（RX）中断掩码中禁用 RBUE 启用“接收缓冲区不可用”（RX Buffer Unavailable, RBUE）中断不仅无益，反而会在高接收负载下触发 MAC 中断风暴。当 DMA 耗尽接收描述符（descriptors）时，会持续触发 RBUE 中断，直到软件重新填充接收环。 然而，RBUE 是冗余的：常规的接收完成中断（RIE）已能触发 NAPI 子系统，后者处理已完成的描述符并重新填充接收环，从而使 DMA 恢复运
Possible ATT&CK Techniques 1 AI
T1499 · Endpoint Denial of ServiceAffected Version Matrix 16
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| Linux | Linux | d6ddfacd95c79d43465d4a85dffb1c9beca343a9< 8c9d57b5dc098b84631d0b3559c84c499ea2170a |
affected |
d6ddfacd95c79d43465d4a85dffb1c9beca343a9< 7a10e54e42a8f73a8d731f5a281fc06bb41b9250 |
affected | ||
d6ddfacd95c79d43465d4a85dffb1c9beca343a9< 6b3b91433d5f4eae6865cdaa96f40cd67849e1f6 |
affected | ||
d6ddfacd95c79d43465d4a85dffb1c9beca343a9< 74dbb85a6a254b5fc1f265a6cd61b2ba9d9221d7 |
affected | ||
d6ddfacd95c79d43465d4a85dffb1c9beca343a9< 0b1a5d3647ce07c27a9fffefc11a8cbf7d7b25ce |
affected | ||
d6ddfacd95c79d43465d4a85dffb1c9beca343a9< 87e2826ed2058747ddf014c082569a46bfadd96b |
affected | ||
d6ddfacd95c79d43465d4a85dffb1c9beca343a9< d3265c19b35d036bba327b36b5366bee76b0157c |
affected | ||
4.19 |
affected | ||
| … +8 more rows | |||
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I. Basic Information for CVE-2026-93830
Vulnerability Information
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Vulnerability Title
net: stmmac: xgmac2: disable RBUE in default RX interrupt mask
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved:
net: stmmac: xgmac2: disable RBUE in default RX interrupt mask
Enabling the RX Buffer Unavailable (RBUE) interrupt is counterproductive
and can trigger a MAC interrupt storm under heavy RX pressure. When the
DMA runs out of RX descriptors it fires RBUE continuously until software
refills the ring.
However, RBUE is redundant: the normal RX completion interrupt (RIE)
already triggers NAPI, which processes completed descriptors and refills
the ring, causing the DMA to resume. The RBUE handler itself only sets
handle_rx - the same outcome as RIE.
On Agilex5 under heavy RX pressure, the MAC interrupt (which includes
RBUE) was observed firing 1,821,811,555 times against only 2,618,627
actual RX completions - a ~695x ratio - confirming the severity of the
storm.
RBUE does not provide OOM recovery. If page_pool is exhausted,
stmmac_rx_refill() cannot advance the DMA tail pointer, the DMA stays
suspended, and RBUE fires again on the next NAPI completion - a storm
with no forward progress. This patch trades that storm for a clean
stall with the same RX outcome. Proper OOM recovery is a pre-existing
gap outside the scope of this fix.
Note: as a consequence of disabling RBUE, the rx_buf_unav_irq ethtool
counter will always read 0 on XGMAC2 devices. This behaviour is already
inconsistent across DWMAC core versions.
Remove RBUE from XGMAC_DMA_INT_DEFAULT_EN and XGMAC_DMA_INT_DEFAULT_RX
to prevent the interrupt storm while keeping normal RX handling intact.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Affected Products
II. Public POCs for CVE-2026-93830
| # | POC Description | Source Link | Shenlong Link |
|---|
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Patches & Fixes for CVE-2026-93830 (7)
Same Patch Batch · Linux · 2026-09-24 · 234 CVEs total
| CVE-2026-93207 | 9.8 CRITICAL | SUNRPC: Zero rpc_gss_wire_cred at svcauth_gss_decode_credbody() entry |
| CVE-2026-97413 | 9.8 CRITICAL | RDMA/rtrs-srv: Fix integer underflow in process_read and process_write |
| CVE-2026-93228 | 9.1 CRITICAL | svcrdma: Reject Write/Reply chunks with segcount 0 |
| CVE-2026-93799 | 8.8 HIGH | wifi: iwlwifi: mvm: validate sta_id in BA window status notif |
| CVE-2026-97442 | 8.8 HIGH | wifi: ath11k: fix invalid data access in ath11k_dp_rx_h_undecap_nwifi |
| CVE-2026-97409 | 8.8 HIGH | nvme-fc: Do not cancel requests in io target before it is initialized |
| CVE-2026-93806 | 8.8 HIGH | wifi: cfg80211: validate assoc response length before status and IE access |
| CVE-2026-93793 | 8.8 HIGH | wifi: iwlwifi: mvm: validate TX_CMD response layout |
| CVE-2026-93790 | 8.8 HIGH | wifi: iwlwifi: mvm: fix out-of-bounds tid_data access in BA notif |
| CVE-2026-93284 | 8.8 HIGH | drm/pagemap: dma-unmap pages before handling migration errors |
| CVE-2026-93280 | 8.8 HIGH | greybus: audio: bound the topology section sizes against the fetched size |
| CVE-2026-97509 | 8.8 HIGH | thunderbolt: Keep XDomain reference during the lifetime of a service |
| CVE-2026-93827 | 8.4 HIGH | virtio-fs: avoid double-free on failed queue setup |
| CVE-2026-97452 | 8.4 HIGH | ACPICA: Prevent adding invalid references |
| CVE-2026-97451 | 8.4 HIGH | ACPICA: Fix integer overflow in acpi_ex_opcode_3A_1T_1R() (mid_op) |
| CVE-2026-97450 | 8.4 HIGH | ACPICA: validate handler object type in two places |
| CVE-2026-97455 | 8.4 HIGH | ACPICA: Fix use-after-free in acpi_ds_terminate_control_method() |
| CVE-2026-97433 | 8.2 HIGH | nvme: validate FDP configuration descriptor sizes |
| CVE-2026-93787 | 8.1 HIGH | smb: client: bound dirent name against end of SMB response in cifs_filldir |
| CVE-2026-93786 | 8.1 HIGH | ksmbd: preserve VFS inherited POSIX ACL mask |
Showing top 20 of 234 CVEs. View all on vendor page → →
IV. Related Vulnerabilities
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Same vendor: Linux
-
CVE-2026-98384
bpf: Fix out-of-bounds read of sk_protocol in bpf_sock_destr -
CVE-2026-98383
bpf: Disallow bpf_skb_pull_data() for LWT_SEG6LOCAL -
CVE-2026-98382
bpf: Reject dev-bound-only programs on other devices -
CVE-2026-98381
veth: manage XDP program pointers during channel resize -
CVE-2026-98380
net/sched: reject IDR error pointers when deleting actions
V. Comments for CVE-2026-93830
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