VulnerabilityPublished 23 Oct 2026

CVE-2026-99025: Linux kernel · openvswitch: fix soft lockup in the netlink flow dump

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in c995c52eba1926a5e82823fa5573a6f1b1010e5d : patch Linux kernel soon.

Data as of 26 Oct 2026, 13:07 UTC

Severity

High

Rated High by Threat Radar's AI analysis · CVSS not yet scored by NVD

EPSS: 0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in c995c52eba1926a5e82823fa5573a6f1b1010e5d, b872de585edff534056c65ba30970b68499fca14, aaaaf87ea99b8766c9a8aa0e71aa42e6bc8a5320 +2

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.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 63e7959c4b9bd6f791061c460a22d9ee32ae2240, < c995c52eba1926a5e82823fa5573a6f1b1010e5d	Fixed in c995c52eba1926a5e82823fa5573a6f1b1010e5d
LinuxLinux	Affected ≥ 63e7959c4b9bd6f791061c460a22d9ee32ae2240, < b872de585edff534056c65ba30970b68499fca14	Fixed in b872de585edff534056c65ba30970b68499fca14
LinuxLinux	Affected ≥ 63e7959c4b9bd6f791061c460a22d9ee32ae2240, < aaaaf87ea99b8766c9a8aa0e71aa42e6bc8a5320	Fixed in aaaaf87ea99b8766c9a8aa0e71aa42e6bc8a5320
LinuxLinux	Affected ≥ 63e7959c4b9bd6f791061c460a22d9ee32ae2240, < 80db24f3c16fdeef85460d9d66a4aae7a9cb92b4	Fixed in 80db24f3c16fdeef85460d9d66a4aae7a9cb92b4
LinuxLinux	Affected ≥ 63e7959c4b9bd6f791061c460a22d9ee32ae2240, < 55f12552b00a34ca7ab5cf2d2b5ed02f8f06a965	Fixed in 55f12552b00a34ca7ab5cf2d2b5ed02f8f06a965
LinuxLinux	Affected =3.16	Fixed in–

AI-suggested

A fix for this vulnerability is available in the Linux kernel, as indicated by the fixed commit versions. Users should update to a kernel version that includes these fixes. No additional mitigation is required beyond applying the official patch.

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 from the way softirqs are handled during flow statistics retrieval, leading to the dumping thread monopolizing CPU softirq processing and causing a system hang. The fix involves holding bottom halves off across the entire callback to prevent unbounded softirq processing and ensure proper CPU scheduling.

Impact

The vulnerability can cause a soft lockup and kernel panic on systems running the affected Linux kernel version with openvswitch, particularly under heavy datapath flow loads. This results in system instability and potential downtime due to the CPU being monopolized by the dumping thread's softirq processing without yielding.

Summary

CVE-2026-99025 addresses a soft lockup vulnerability in the Linux kernel's openvswitch netlink flow dump functionality. The problem occurs because ovs_flow_cmd_dump() calls ovs_flow_stats_get() for each flow, releasing stats->lock with spin_unlock_bh() multiple times per CPU. Each release triggers local_bh_enable(), which runs pending softirq backlog in the dumping thread's context. On busy CPUs, the backlog refills as fast as it drains, causing the dumping thread to become the CPU's softirq engine, preventing it from sleeping or being preempted. This results in a soft lockup and kernel panic. The fix applies a bottom half (BH) off region across the entire callback, similar to ctnetlink_dump_table(), preventing nested spin_unlock_bh() calls from draining softirqs and allowing proper CPU scheduling under CONFIG_PREEMPT.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 26 Oct 2026, 09:57 UTC

Technical details

References

Community reviews

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