CVE-2026-99025: Linux kernel · openvswitch: fix soft lockup in the netlink flow dump
Affects Linux kernelSource GCVE Database
Not known to be exploited.
Data as of 28 Oct 2026, 01:57 UTC
Rated by Threat Radar · CVSS not yet scored by NVD
Exploitation evidence
Disclosed: evidence found.
CVE published 23 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 26.10linuxpkg:deb/ubuntu/linux?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-oraclepkg:deb/ubuntu/linux-oracle?arch=source&distro=stonkingOther 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 fix is available that changes the locking behavior to hold bottom halves off across the entire callback, preventing the softirq backlog from causing a soft lockup. Users should apply the fixed linux-aws kernel versions listed to remediate this issue. Since this is a kernel-level fix, upgrading to a patched kernel release is the recommended mitigation. No additional vendor advisory content or cloud service patching is indicated.
Description
A vulnerability in the Linux kernel's openvswitch component caused a soft lockup during netlink flow dumps on production compute nodes with thousands of datapath flows. The issue arises because the softirq backlog refills as fast as it drains, causing the dumping thread to monopolize CPU time without rescheduling, leading to a soft lockup. The fix involves holding bottom halves (BH) off across the entire callback to prevent draining softirqs prematurely, thus avoiding the lockup. This fix trades off preemption under CONFIG_PREEMPT but keeps the BH-off region short and bounded by the flow count.
References
- ubuntu.com/security/CVE-2026-99025 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-99025 (opens in a new tab)
- git.kernel.org/stable/c/55f12552b00a34ca7ab5cf2d2b5ed02f8f06a965 (opens in a new tab)
- git.kernel.org/stable/c/80db24f3c16fdeef85460d9d66a4aae7a9cb92b4 (opens in a new tab)
- git.kernel.org/stable/c/aaaaf87ea99b8766c9a8aa0e71aa42e6bc8a5320 (opens in a new tab)
- git.kernel.org/stable/c/b872de585edff534056c65ba30970b68499fca14 (opens in a new tab)
- git.kernel.org/stable/c/c995c52eba1926a5e82823fa5573a6f1b1010e5d (opens in a new tab)