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

CVE-2026-98294: Bluetooth: hci_qca: Do not write to the serial port after it is closed

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: 0.17% (FIRST EPSS).
  • Fixed version: Linux Linux 15754e4ec47ac5d117c9609c34a49ed6980ac4a1, 4e93c65f87825e1e012bce56615320aeb123815d, a5414b0a9464b863733c8bd97493cb443a210ec4; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 Release Notes.

Low priority for now. Upgrade to Linux Linux 15754e4ec47ac5d117c9609c34a49ed6980ac4a1, 4e93c65f87825e1e012bce56615320aeb123815d, a5414b0a9464b863733c8bd97493cb443a210ec4; 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: Bluetooth: hci_qca: Do not write to the serial port after it is closed hci_uart_close() closes the serdev port if HCI_QUIRK_NON_PERSISTENT_SETUP is set (for example, for the WCN399x family). A failed hci_dev_open_sync() following a successful qca_setup() calls hdev->close() but not hdev->shutdown(), so the port is closed while power->vregs_on is left true. qca_serdev_remove() then passes its power->vregs_on test and calls qca_power_off(), which writes to the closed port unconditionally. Seen on a WCN3988 by unbinding the driver after a controller failure. The trace below is from a 7.0.0 based kernel, where qca_power_off() was still named qca_power_shutdown(): Unable to handle kernel NULL pointer dereference at virtual address 0000000000000038 Call trace: tty_set_termios+0x50/0x238 (P) ttyport_set_baudrate+0x84/0xc0 serdev_device_set_baudrate+0x24/0x40 qca_power_shutdown+0x158/0x1fc [hci_uart] qca_serdev_remove+0x54/0x68 [hci_uart] serdev_drv_remove+0x1c/0x2c device_remove+0x4c/0x80 device_release_driver_internal+0x1cc/0x224 device_driver_detach+0x18/0x24 unbind_store+0xb4/0xc0 Check HCI_UART_PROTO_READY, which hci_uart_close() clears in the same place it closes the port, before writing to it. The regulator disable is left unconditional so the controller is still powered down. The dangling serport->tty that turns this into a use-after-free is addressed in a separate patch.

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

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—

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

    • 4.19affected
    • fa9ad876b8e0ebd2b4367ef1580f89be64ebd5d3 and later · before a5414b0a9464b863733c8bd97493cb443a210ec4affected · git
    • fa9ad876b8e0ebd2b4367ef1580f89be64ebd5d3 and later · before 15754e4ec47ac5d117c9609c34a49ed6980ac4a1affected · git
    • fa9ad876b8e0ebd2b4367ef1580f89be64ebd5d3 and later · before 4e93c65f87825e1e012bce56615320aeb123815daffected · git
    • before 4.19not 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-2026-98292Oct 6, 2026 · Bluetooth: btmtksdio, btmtkuart: validate WMT event length before struct access
    0Monitor
  • ← EarlierCVE-2026-98293Oct 6, 2026 · Bluetooth: ISO: Fix parent socket leak in iso_conn_ready()
    0Monitor
  • Later →CVE-2026-98295Oct 6, 2026 · Bluetooth: coredump: Quiesce dump work on unregister
    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 Linux15754e4ec47ac5d117c9609c34a49ed6980ac4a1Vendor (CNA)
Linux Linux4e93c65f87825e1e012bce56615320aeb123815dVendor (CNA)
Linux Linuxa5414b0a9464b863733c8bd97493cb443a210ec4Vendor (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 29, 2026+23 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.

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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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