CVE-2026-93830: Linux kernel · net: stmmac: xgmac2: disable RBUE in default RX interrupt mask
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.5 High.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 41% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 24 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A patch is available that disables the RBUE interrupt in the default RX interrupt mask for the stmmac xgmac2 driver, preventing the interrupt storm while preserving normal RX processing. Users should apply the official kernel updates that include this fix. No additional mitigation is required as the patch addresses the root cause. Note that the rx_buf_unav_irq ethtool counter will always show zero on affected devices after the fix, which is expected behavior.
Description
A vulnerability in the Linux kernel's stmmac xgmac2 network driver caused an interrupt storm due to enabling the RX Buffer Unavailable (RBUE) interrupt by default. This interrupt storm occurs under heavy receive (RX) pressure when the DMA runs out of RX descriptors, firing RBUE continuously without forward progress, leading to degraded system performance. The issue was resolved by disabling RBUE in the default RX interrupt mask, preventing the interrupt storm while maintaining normal RX handling. This fix trades the storm for a clean stall with the same RX outcome. The vulnerability affects specific Linux kernel versions listed and has a CVSS score of 7.5, indicating medium severity with high impact on availability.
References
- ubuntu.com/security/CVE-2026-93830 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-93830 (opens in a new tab)
- git.kernel.org/stable/c/d3265c19b35d036bba327b36b5366bee76b0157c (opens in a new tab)
- git.kernel.org/stable/c/0b1a5d3647ce07c27a9fffefc11a8cbf7d7b25ce (opens in a new tab)
- git.kernel.org/stable/c/87e2826ed2058747ddf014c082569a46bfadd96b (opens in a new tab)
- nvd.nist.gov/vuln/detail/CVE-2026-93830 (opens in a new tab)
- git.kernel.org/stable/c/6b3b91433d5f4eae6865cdaa96f40cd67849e1f6 (opens in a new tab)
- git.kernel.org/stable/c/74dbb85a6a254b5fc1f265a6cd61b2ba9d9221d7 (opens in a new tab)
- git.kernel.org/stable/c/7a10e54e42a8f73a8d731f5a281fc06bb41b9250 (opens in a new tab)
- git.kernel.org/stable/c/8c9d57b5dc098b84631d0b3559c84c499ea2170a (opens in a new tab)