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NVD / CVE Program· CNA Linux

CVE-2026-64409: Bluetooth: btmtksdio: fix infinite loop in btmtksdio_txrx_work()

Noroxi assessment

Priority: Monitor (action score 22/100)

  • 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: 0.12% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 0039bdde36b23ccf1196635f1d52c5490481544d, 0f0a83e26a9c7fd4b243c315ce07161d2496d83d, 466540e045d01fcacf383a5beb8a2dad2fc53a26; azl3 kernel 6.6.144.1-1 on Azure Linux 3.0 6.6.145.2-1.

Low priority for now. Upgrade to Linux Linux 0039bdde36b23ccf1196635f1d52c5490481544d, 0f0a83e26a9c7fd4b243c315ce07161d2496d83d, 466540e045d01fcacf383a5beb8a2dad2fc53a26; azl3 kernel 6.6.144.1-1 on Azure Linux 3.0 6.6.145.2-1 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: btmtksdio: fix infinite loop in btmtksdio_txrx_work() Every once in a while we see a hung btmtksdio_flush() task: INFO: task kworker/u17:0:189 blocked for more than 122 seconds. __cancel_work_timer+0x3f4/0x460 cancel_work_sync+0x1c/0x2c btmtksdio_flush+0x2c/0x40 hci_dev_open_sync+0x10c4/0x2190 [..] It all boils down to incorrect time_is_before_jiffies() usage in btmtksdio_txrx_work(). The btmtksdio_txrx_work() loop is expected to be terminated if running for longer than 5*HZ. However the timeout check is twisted: time_is_before_jiffies(old_jiffies + 5*HZ) evaluates to true when old_jiffies + 5*HZ is in the past i.e. when a timeout has occurred. Using OR with time_is_before_jiffies(txrx_timeout) means that: - before the 5-second timeout: the condition is `int_status || false`, so it loops as long as there are pending interrupts. - after the 5-second timeout: the condition becomes `int_status || true`, which is always true. When the loop becomes infinite btmtksdio_txrx_work() loop never terminates and never releases the SDIO host. Fix loop termination condition to actually enforce a 5*HZ timeout.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Jul 25, 2026
Updated
Sep 4, 2026
EPSS
0.1% · 2th percentile

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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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.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel5.17 and later · before 6.1.178
  • linux linux kernel6.2 and later · before 6.6.145
  • linux linux kernel6.7 and later · before 6.12.96
  • linux linux kernel6.13 and later · before 6.18.39
  • linux linux kernel6.19 and later · before 7.1.4

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

    • 5.17affected
    • 26270bc189ea4b5a8356ec99561357fc87f00b32 and later · before f6682c23b6fac4780d297ae4662053d17e58fd52affected · git
    • 26270bc189ea4b5a8356ec99561357fc87f00b32 and later · before 466540e045d01fcacf383a5beb8a2dad2fc53a26affected · git
    • 26270bc189ea4b5a8356ec99561357fc87f00b32 and later · before 7b429d611060e87752e848851815537963726493affected · git
    • 26270bc189ea4b5a8356ec99561357fc87f00b32 and later · before 0039bdde36b23ccf1196635f1d52c5490481544daffected · git
    • 26270bc189ea4b5a8356ec99561357fc87f00b32 and later · before 0f0a83e26a9c7fd4b243c315ce07161d2496d83daffected · git
    • 26270bc189ea4b5a8356ec99561357fc87f00b32 and later · before a257407e2bbbb099ed427719a50563f67fa366d8affected · git
    • before 5.17not affected · semver
    • 6.1.178 and later · up to and including 6.1.*not affected · semver
    • 6.6.145 and later · up to and including 6.6.*not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.180-16.1.180-1
Debian:12linux-6.12before 6.12.100-1~deb12u16.12.100-1~deb12u1
Debian:13linuxbefore 6.12.96-16.12.96-1
Debian:14linuxbefore 7.1.4-17.1.4-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2026-64405Jul 25, 2026 · Bluetooth: hci_conn: Fix null ptr deref in hci_abort_conn()
    22Monitor
  • ← EarlierCVE-2026-64407Jul 25, 2026 · Bluetooth: btnxpuart: Fix out-of-bounds firmware read in nxp_recv_fw_req_v3()
    28Monitor
  • Later →CVE-2026-64410Jul 25, 2026 · netfilter: flowtable: IPIP tunnel hardware offload is not yet support
    39Monitor

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 Linux0039bdde36b23ccf1196635f1d52c5490481544dVendor (CNA)
Linux Linux0f0a83e26a9c7fd4b243c315ce07161d2496d83dVendor (CNA)
Linux Linux466540e045d01fcacf383a5beb8a2dad2fc53a26Vendor (CNA)
Linux Linux7b429d611060e87752e848851815537963726493Vendor (CNA)
Linux Linuxa257407e2bbbb099ed427719a50563f67fa366d8Vendor (CNA)
Linux Linuxf6682c23b6fac4780d297ae4662053d17e58fd52Vendor (CNA)
azl3 kernel 6.6.144.1-1 on Azure Linux 3.06.6.145.2-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:linux6.1.180-1 · Debian:12Package registry (OSV)
debian:linux-6.126.12.100-1~deb12u1 · Debian:12Package 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.

No dated events beyond publication.

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

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

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.

  • CVE-2026-3144894 days apartext4: avoid infinite loops caused by residual data
    37Monitor
  • CVE-2026-638896 days apartscsi: scsi_transport_fc: Widen FPIN pname walker counter to u32
    32Monitor
  • CVE-2026-5293331 days apartio_uring/poll: fix signed comparison in io_poll_get_ownership()
    31Monitor
  • CVE-2026-639686 days apartipv6: fix possible infinite loop in fib6_select_path()
    30Monitor
  • CVE-2026-641486 days apartpds_core: fix error handling in pdsc_devcmd_wait
    30Monitor
  • CVE-2026-4605259 days apartceph: only d_add() negative dentries when they are unhashed
    30Monitor

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

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-835 · Loop with Unreachable Exit Condition ('Infinite Loop')

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

nvd-primary

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. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (5 more)

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

All records