In the Linux kernel, the following vulnerability has been resolved:
xen-netfront: Fix NULL sring after live migration
A NAPI is setup for each network sring to poll data to kernel
The sring with source host is destroyed before live migration and
new sring with target host is setup after live migration.
The NAPI for the old sring is not deleted until setup new sring
with target host after migration. With busy_poll/busy_read enabled,
the NAPI can be polled before got deleted when resume VM.
BUG: unable to handle kernel NULL pointer dereference at
0000000000000008
IP: xennet_poll+0xae/0xd20
PGD 0 P4D 0
Oops: 0000 [#1] SMP PTI
Call Trace:
finish_task_switch+0x71/0x230
timerqueue_del+0x1d/0x40
hrtimer_try_to_cancel+0xb5/0x110
xennet_alloc_rx_buffers+0x2a0/0x2a0
napi_busy_loop+0xdb/0x270
sock_poll+0x87/0x90
do_sys_poll+0x26f/0x580
tracing_map_insert+0x1d4/0x2f0
event_hist_trigger+0x14a/0x260
finish_task_switch+0x71/0x230
__schedule+0x256/0x890
recalc_sigpending+0x1b/0x50
xen_sched_clock+0x15/0x20
__rb_reserve_next+0x12d/0x140
ring_buffer_lock_reserve+0x123/0x3d0
event_triggers_call+0x87/0xb0
trace_event_buffer_commit+0x1c4/0x210
xen_clocksource_get_cycles+0x15/0x20
ktime_get_ts64+0x51/0xf0
SyS_ppoll+0x160/0x1a0
SyS_ppoll+0x160/0x1a0
do_syscall_64+0x73/0x130
entry_SYSCALL_64_after_hwframe+0x41/0xa6
...
RIP: xennet_poll+0xae/0xd20 RSP: ffffb4f041933900
CR2: 0000000000000008
---[ end trace f8601785b354351c ]---
xen frontend should remove the NAPIs for the old srings before live
migration as the bond srings are destroyed
There is a tiny window between the srings are set to NULL and
the NAPIs are disabled, It is safe as the NAPI threads are still
frozen at that time
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (5.5): severity, escalated by confirmed exploitation. This CVE's 5.5 is its impact severity (EG Severity), not escalated.
- EG Severity
- 5.5 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
- EG Likelihood
- 0.3% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-25). FIRST's exploitation probability, not an EchelonGraph model.
- Confirmed exploitation
- None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
- EG Priority
- SSVC Track at medium mission impactTrack at every mission impact level.CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.
SSVC (CISA's decision table, applied by EchelonGraph)Track at every mission impact level.
A fix is available. Apply it within your standard update timelines.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table
BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.
The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it