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CVE-2026-93830

Vulnérabilité élevée dans Linux (Linux)

CVSS 7.5 · Élevée
EPSS 0.5%
Linux•Linux•Versions : <=6.1.*, <=6.12.*, <d3265c19b35d036bba327b36b5366bee76b0157c, 0, 6.18.53, 4.19, 5.10.271, 6.6.158, <0b1a5d3647ce07c27a9fffefc11a8cbf7d7b25ce, <7a10e54e42a8f73a8d731f5a281fc06bb41b9250, <=5.10.*, <=6.6.*, 6.1.189, <87e2826ed2058747ddf014c082569a46bfadd96b, <=6.18.*, 5.15.222, <6b3b91433d5f4eae6865cdaa96f40cd67849e1f6, <4.19, <74dbb85a6a254b5fc1f265a6cd61b2ba9d9221d7, <8c9d57b5dc098b84631d0b3559c84c499ea2170a, <=*, <=5.15.*, d6ddfacd95c79d43465d4a85dffb1c9beca343a9, 7.2, 6.12.111

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.

Gravité et risque d'exploitation

CVE-2026-93830 obtient un score CVSS de 7.5/10, soit une gravité élevée. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.49 %, ce qui la place devant 40.8 % des CVE référencées.

Que faire ?

  • Vérifiez si Linux (versions <=6.1.*, <=6.12.*, <d3265c19b35d036bba327b36b5366bee76b0157c, 0, 6.18.53, 4.19, 5.10.271, 6.6.158, <0b1a5d3647ce07c27a9fffefc11a8cbf7d7b25ce, <7a10e54e42a8f73a8d731f5a281fc06bb41b9250, <=5.10.*, <=6.6.*, 6.1.189, <87e2826ed2058747ddf014c082569a46bfadd96b, <=6.18.*, 5.15.222, <6b3b91433d5f4eae6865cdaa96f40cd67849e1f6, <4.19, <74dbb85a6a254b5fc1f265a6cd61b2ba9d9221d7, <8c9d57b5dc098b84631d0b3559c84c499ea2170a, <=*, <=5.15.*, d6ddfacd95c79d43465d4a85dffb1c9beca343a9, 7.2, 6.12.111) est présent sur votre parc.
  • Appliquez le correctif ou la version corrigée indiqués dans les références de l'éditeur.
  • À défaut de correctif, limitez l'exposition (filtrage réseau, désactivation du composant).
  • Automatisez la détection : les agents CVE Heimdall (gratuits, open source) corrèlent l'inventaire de vos serveurs avec la base CVE.

Références

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