VulnerabilityPublished 23 Oct 2026

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

Source GCVE Database

Authoritative record:CVE-2026-99025· High

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

Data as of 26 Oct 2026, 12:55 UTC

Severity

High

Rated by Threat Radar · 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.

ghsa-25wv-6mrm-3cpw

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–

Description

In the Linux kernel, the following vulnerability has been resolved: openvswitch: fix soft lockup in the netlink flow dump A production compute node carrying a few thousand datapath flows hit a soft lockup inside a single netlink flow dump and panicked. ovs_flow_cmd_dump() calls ovs_flow_stats_get() for every flow it emits, and that releases stats->lock with spin_unlock_bh() once per CPU that has touched the flow. Every release is a local_bh_enable(), and each one runs the pending softirq backlog in the dumping thread's own context. The skb bounds the flows one callback emits, but not the softirq work it absorbs. On a CPU that carries the box's packet load the backlog refills as fast as it drains, so the dumping thread becomes that CPU's softirq engine. It never sleeps and it has no reschedule point, so under voluntary preemption nothing can take the CPU away from it: neither the ksoftirqd the kernel woke to take the work over, nor the stopper thread the softlockup detector dispatches to refresh its timestamp. Hold BH off across the whole callback instead, the way ctnetlink_dump_table() does, so the nested spin_unlock_bh() stop draining softirqs. The loop already runs under rcu_read_lock() and cannot sleep. What it gives up is preemption under CONFIG_PREEMPT, since a BH-off region is not preemptible outside PREEMPT_RT. The region stays short: the skb caps the flows one callback emits, and empty buckets cost no skb space but are each visited once per dump, as the cursor only moves forward. The table grows on insert and shrinks only on flush, so the walk is bounded by the largest flow count the datapath has held. The softirq backlog the callback used to absorb has no bound at all.

References

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