Allocation of Resources Without Limits or Throttling Affecting kernel-64k-devel-matched package, versions *
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-CENTOS10-KERNEL64KDEVELMATCHED-20271267
- published30 Sept 2026
- disclosed24 Sept 2026
Introduced: 24 Sep 2026
NewCVE-2026-93830 (opens in a new tab)How to fix?
There is no fixed version for Centos:10 kernel-64k-devel-matched.
NVD Description
Note: Versions mentioned in the description apply only to the upstream kernel-64k-devel-matched package and not the kernel-64k-devel-matched package as distributed by Centos.
See How to fix? for Centos:10 relevant fixed versions and status.
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.
References
- https://bugzilla.redhat.com/show_bug.cgi?id=2540518
- https://access.redhat.com/security/cve/CVE-2026-93830
- https://git.kernel.org/stable/c/0b1a5d3647ce07c27a9fffefc11a8cbf7d7b25ce
- https://git.kernel.org/stable/c/87e2826ed2058747ddf014c082569a46bfadd96b
- https://git.kernel.org/stable/c/d3265c19b35d036bba327b36b5366bee76b0157c