CVE-2026-98347: Linux kernel · IB/IPoIB: Avoid restoring OPER_UP after multicast flush
Affects Linux kernelSource GCVE Database
Not known to be exploited.
Data as of 28 Oct 2026, 01:28 UTC
Rated by Threat Radar · CVSS not yet scored by NVD
Exploitation evidence
Disclosed: evidence found.
CVE published 6 Oct 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.
Description
In the Linux kernel, the following vulnerability has been resolved: IB/IPoIB: Avoid restoring OPER_UP after multicast flush ipoib_ib_dev_flush_light() temporarily clears IPOIB_FLAG_OPER_UP to prevent multicast joins while ipoib_mcast_dev_flush() is running, and restores the flag afterwards if it was previously set. This restore races with ipoib_ib_dev_down(). If the interface is brought down while the flush is in progress, ipoib_ib_dev_down() clears IPOIB_FLAG_OPER_UP, but the flush path may set it again after the device has already gone down. Since commit 894021a75291 ("IB/ipoib: Make the carrier_on_task race aware"), ipoib_mcast_carrier_on_task() relies on IPOIB_FLAG_OPER_UP being cleared to terminate its rtnl_trylock() retry loop. If the flag is left set after shutdown, the workqueue retries forever, causing teardown to deadlock when ipoib_ndo_uninit() waits in destroy_workqueue() while holding RTNL. Instead of overloading IPOIB_FLAG_OPER_UP to block multicast joins during a light flush, introduce a dedicated IPOIB_FLAG_MCAST_FLUSH flag. Use it together with IPOIB_FLAG_OPER_UP to determine whether multicast joins are allowed, avoiding the race with device shutdown.
References
- ubuntu.com/security/CVE-2026-98347 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-98347 (opens in a new tab)
- git.kernel.org/linus/9a141d3dc869d18b2eab35e999f4790a9b84e40f (opens in a new tab)
- git.kernel.org/stable/c/188b334a6db36a8e0bfaaf59bc4020639a0f3aad (opens in a new tab)
- git.kernel.org/stable/c/1b11e4b55b41d9e69a8e8d07622614202e2eaca9 (opens in a new tab)
- git.kernel.org/stable/c/1ff3add37c329704ec46181b4ae4f00f9f16ce6f (opens in a new tab)
- git.kernel.org/stable/c/326f7d34bd7e64de535566b65c0533b640df5a81 (opens in a new tab)
- git.kernel.org/stable/c/5ad925d45f28464a5e043c9620880bb6a030da89 (opens in a new tab)
- git.kernel.org/stable/c/9a141d3dc869d18b2eab35e999f4790a9b84e40f (opens in a new tab)
- git.kernel.org/stable/c/b72f38929f4b5aa83161fd3b22a7327207e51ec5 (opens in a new tab)
- git.kernel.org/stable/c/f973769fb7cb33ba0d4a64b7dcfee0cabaead938 (opens in a new tab)