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CVE.org (no NVD analysis yet)· CNA Linux

CVE-2026-98286: drop_monitor: use timer_shutdown_sync() to prevent timer rearming during teardown

Noroxi assessment

Priority: Monitor (action score 0/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.16% (FIRST EPSS).
  • Fixed version: Linux Linux 5.11, 5.12, 9616b0c67fbd8cc0b49de7b26cdf2ab33747c80e; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 Release Notes.

Low priority for now. Upgrade to Linux Linux 5.11, 5.12, 9616b0c67fbd8cc0b49de7b26cdf2ab33747c80e; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 Release Notes or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: drop_monitor: use timer_shutdown_sync() to prevent timer rearming during teardown In drop_monitor teardown paths (net_dm_trace_off_set(), net_dm_hw_monitor_stop(), and error unwind paths in net_dm_trace_on_set() and net_dm_hw_monitor_start()), per-CPU timers are stopped using timer_delete_sync() followed by cancel_work_sync(). However, there is a circular dependency between send_timer and dm_alert_work: 1) sched_send_work() (timer callback) schedules dm_alert_work. 2) send_dm_alert() / net_dm_hw_summary_work() calls reset_per_cpu_data() or net_dm_hw_reset_per_cpu_data(). 3) If memory allocation fails under memory pressure in the reset function, it re-arms the timer via mod_timer(&data->send_timer, ...). If dm_alert_work is running concurrently while timer_delete_sync() executes on another CPU, an allocation failure in the worker will re-arm the timer after timer_delete_sync() has already returned. Once cancel_work_sync() completes and module_put() is called, the timer remains active in the timer wheel. If the module is then unloaded, the timer will fire and execute sched_send_work() in freed memory, triggering a kernel panic / use-after-free. Switch from timer_delete_sync() to timer_shutdown_sync(). This guarantees that any in-flight timer handler has finished and prevents subsequent re-arming attempts from running workers from succeeding. When monitoring is restarted later, timer_setup() is invoked, which cleanly re-initializes the timer.

—No exploit Fix available
Published
Oct 6, 2026
Updated
Oct 19, 2026
EPSS
0.1% · 5th percentile
CWE
—

Report tools

JSON

Action score

0

Monitor

Low priority for now.

CVSS
0 / 40 · —
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

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Noroxi analysis

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 2514c7ad115e762562c7bdd58bb1ab3425a98245, 439b1164da3612ec7e186e1dc314471e7190bfc7, 5.12affected
    • 9398e9c0b1d44eeb700e9e766c02bcc765c82570 and later · before 9616b0c67fbd8cc0b49de7b26cdf2ab33747c80eaffected · git
    • 9398e9c0b1d44eeb700e9e766c02bcc765c82570 and later · before bda4d9525fb91a2388ee09669421b8d505290864affected · git
    • 9398e9c0b1d44eeb700e9e766c02bcc765c82570 and later · before c391a40f71886b28c082b47270f0e856fa3e1150affected · git
    • 5.10.27 and later · before 5.11affected · semver
    • 5.11.11 and later · before 5.12affected · semver
    • before 5.12not affected · semver
    • 6.18.54 and later · up to and including 6.18.*not affected · semver
    • 7.2.8 and later · up to and including 7.2.*not affected · semver
    • 7.3 and laternot affected · original_commit_for_fix

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxfrom 0—
Debian:14linuxbefore 7.2.8-17.2.8-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-98284Oct 6, 2026 · netlink: do not free nlk->groups while lockless readers can use it
    0Monitor
  • ← EarlierCVE-2026-98285Oct 6, 2026 · net: bridge: vlan: fix bugs caused by switchdev deletion errors
    0Monitor
  • Later →CVE-2026-98287Oct 6, 2026 · pppoatm: ensure a writable skb header and linear data
    0Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux5.11Vendor (CNA)
Linux Linux5.12Vendor (CNA)
Linux Linux9616b0c67fbd8cc0b49de7b26cdf2ab33747c80eVendor (CNA)
Linux Linuxbda4d9525fb91a2388ee09669421b8d505290864Vendor (CNA)
Linux Linuxc391a40f71886b28c082b47270f0e856fa3e1150Vendor (CNA)
azl3 kernel 6.6.157.1-1 on Azure Linux 3.0Release NotesMicrosoft (MSRC)
debian:linux7.2.8-1 · Debian:14Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Published
  2. Fix recordedsame day
  3. TodayOct 27, 2026+21 d
EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

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No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

No CVSS vector for this record, so attack conditions can't be derived.

Weakness class (CWE)

—

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Exploit maturity— → none
  2. Fix✗ → ✓

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References

Show all references (2 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

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