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NVD / CVE Program· CNA Linux

CVE-2025-39860: Bluetooth: Fix use-after-free in l2cap_sock_cleanup_listen()

Noroxi assessment

Priority: Monitor (action score 31/100)

  • 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: 0.23% (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 2ca99fc3512a8074de20ee52a87b492dfcc41a4d, 306b0991413b482dbf5585b423022123bb505966, 3dff390f55ccd9ce12e91233849769b5312180c2; azl3 kernel 6.6.104.2-4 on Azure Linux 3.0 6.6.112.1-1.

Low priority for now. Upgrade to Linux Linux 2ca99fc3512a8074de20ee52a87b492dfcc41a4d, 306b0991413b482dbf5585b423022123bb505966, 3dff390f55ccd9ce12e91233849769b5312180c2; azl3 kernel 6.6.104.2-4 on Azure Linux 3.0 6.6.112.1-1 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: Fix use-after-free in l2cap_sock_cleanup_listen() syzbot reported the splat below without a repro. In the splat, a single thread calling bt_accept_dequeue() freed sk and touched it after that. The root cause would be the racy l2cap_sock_cleanup_listen() call added by the cited commit. bt_accept_dequeue() is called under lock_sock() except for l2cap_sock_release(). Two threads could see the same socket during the list iteration in bt_accept_dequeue(): CPU1 CPU2 (close()) ---- ---- sock_hold(sk) sock_hold(sk); lock_sock(sk) <-- block close() sock_put(sk) bt_accept_unlink(sk) sock_put(sk) <-- refcnt by bt_accept_enqueue() release_sock(sk) lock_sock(sk) sock_put(sk) bt_accept_unlink(sk) sock_put(sk) <-- last refcnt bt_accept_unlink(sk) <-- UAF Depending on the timing, the other thread could show up in the "Freed by task" part. Let's call l2cap_sock_cleanup_listen() under lock_sock() in l2cap_sock_release(). [0]: BUG: KASAN: slab-use-after-free in debug_spin_lock_before kernel/locking/spinlock_debug.c:86 [inline] BUG: KASAN: slab-use-after-free in do_raw_spin_lock+0x26f/0x2b0 kernel/locking/spinlock_debug.c:115 Read of size 4 at addr ffff88803b7eb1c4 by task syz.5.3276/16995 CPU: 3 UID: 0 PID: 16995 Comm: syz.5.3276 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xcd/0x630 mm/kasan/report.c:482 kasan_report+0xe0/0x110 mm/kasan/report.c:595 debug_spin_lock_before kernel/locking/spinlock_debug.c:86 [inline] do_raw_spin_lock+0x26f/0x2b0 kernel/locking/spinlock_debug.c:115 spin_lock_bh include/linux/spinlock.h:356 [inline] release_sock+0x21/0x220 net/core/sock.c:3746 bt_accept_dequeue+0x505/0x600 net/bluetooth/af_bluetooth.c:312 l2cap_sock_cleanup_listen+0x5c/0x2a0 net/bluetooth/l2cap_sock.c:1451 l2cap_sock_release+0x5c/0x210 net/bluetooth/l2cap_sock.c:1425 __sock_release+0xb3/0x270 net/socket.c:649 sock_close+0x1c/0x30 net/socket.c:1439 __fput+0x3ff/0xb70 fs/file_table.c:468 task_work_run+0x14d/0x240 kernel/task_work.c:227 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop+0xeb/0x110 kernel/entry/common.c:43 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x3f6/0x4c0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f2accf8ebe9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffdb6cb1378 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00000000000426fb RCX: 00007f2accf8ebe9 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 00007f2acd1b7da0 R08: 0000000000000001 R09: 00000012b6cb166f R10: 0000001b30e20000 R11: 0000000000000246 R12: 00007f2acd1b609c R13: 00007f2acd1b6090 R14: ffffffffffffffff R15: 00007ffdb6cb1490 </TASK> Allocated by task 5326: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:388 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:405 kasan_kmalloc include/linux/kasan.h:260 [inline] __do_kmalloc_node mm/slub.c:4365 [inline] __kmalloc_nopro ---truncated---

HighCVSS 7.8 · v3.1—No exploit Fix available
Published
Sep 19, 2025
Updated
Oct 19, 2026
EPSS
0.2% · 13th percentile

Report tools

JSON

Action score

31

Monitor

Low priority for now.

CVSS
31 / 40 · 7.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
7.8
CNA · Linux
8.0
0.2 point gap

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

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  • when exploit code appears or is weaponized
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  • when EPSS rises 20 points in a week

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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
debiandebian linux

Affected versions

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

  • debian debian linux11.0
  • linux linux kernel4.19.291 and later · before 4.20
  • linux linux kernel5.4.253 and later · before 5.4.299
  • linux linux kernel5.10.190 and later · before 5.10.243
  • linux linux kernel5.15.126 and later · before 5.15.192
  • linux linux kernel4.14.322 and later · before 4.15
  • linux linux kernel6.4.10 and later · before 6.6.105
  • linux linux kernel6.7 and later · before 6.12.46
  • linux linux kernel6.13 and later · before 6.16.6
  • linux linux kernel6.1.45 and later · before 6.1.151
  • linux linux kernel6.17

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

    • 51822644a047eac2310fab0799b64e3430b5a111, 82cdb2ccbe43337798393369f0ceb98699fe6037, 10426afe65c8bf7b24dd0c7be4dcc65f86fc99f9, 6.5affected
    • a2da00d1ea1abfb04f846638e210b5b5166e3c9c and later · before 964cbb198f9c46c2b2358cd1faffc04c1e8248cfaffected · git
    • 06f87c96216bc5cd1094c23492274f77f1d5dd3b and later · before 83e1d9892ef51785cf0760b7681436760dda435aaffected · git
    • fbe5a2fed8156cc19eb3b956602b0a1dd46a302d and later · before 47f6090bcf75c369695d21c3f179db8a56bbbd49affected · git
    • 29fac18499332211b2615ade356e2bd8b3269f98 and later · before 2ca99fc3512a8074de20ee52a87b492dfcc41a4daffected · git
    • 1728137b33c00d5a2b5110ed7aafb42e7c32e4a1 and later · before 6077d16b5c0f65d571eee709de2f0541fb5ef0caaffected · git
    • 1728137b33c00d5a2b5110ed7aafb42e7c32e4a1 and later · before 306b0991413b482dbf5585b423022123bb505966affected · git
    • 1728137b33c00d5a2b5110ed7aafb42e7c32e4a1 and later · before 3dff390f55ccd9ce12e91233849769b5312180c2affected · git
    • 1728137b33c00d5a2b5110ed7aafb42e7c32e4a1 and later · before 862c628108562d8c7a516a900034823b381d3cbaaffected · git
    • 5.4.253 and later · before 5.4.299affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.153-16.1.153-1
Debian:13linuxbefore 6.12.48-16.12.48-1
Debian:14linuxbefore 6.16.6-16.16.6-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • 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
  • CVE-2016-5195Race condition in mm/gup.c in the Linux kernel 2.x through 4.x before 4.8.3 allows local users to gain privileges by leveraging incorrect haKEV
    83Now

Published before and after this one in the same product

  • ← EarlierCVE-2025-39858Sep 19, 2025 · eth: mlx4: Fix IS_ERR() vs NULL check bug in mlx4_en_create_rx_ring
    22Monitor
  • ← EarlierCVE-2025-39859Sep 19, 2025 · ptp: ocp: fix use-after-free bugs causing by ptp_ocp_watchdog
    31Monitor
  • Later →CVE-2025-39861Sep 19, 2025 · Bluetooth: vhci: Prevent use-after-free by removing debugfs files early
    31Monitor

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 Linux2ca99fc3512a8074de20ee52a87b492dfcc41a4dVendor (CNA)
Linux Linux306b0991413b482dbf5585b423022123bb505966Vendor (CNA)
Linux Linux3dff390f55ccd9ce12e91233849769b5312180c2Vendor (CNA)
Linux Linux4.15Vendor (CNA)
Linux Linux4.20Vendor (CNA)
Linux Linux47f6090bcf75c369695d21c3f179db8a56bbbd49Vendor (CNA)
Linux Linux5.10.243Vendor (CNA)
Linux Linux5.15.192Vendor (CNA)
Linux Linux5.4.299Vendor (CNA)
Linux Linux6.1.151Vendor (CNA)
Linux Linux6.5Vendor (CNA)
Linux Linux6077d16b5c0f65d571eee709de2f0541fb5ef0caVendor (CNA)
Linux Linux83e1d9892ef51785cf0760b7681436760dda435aVendor (CNA)
Linux Linux862c628108562d8c7a516a900034823b381d3cbaVendor (CNA)
Linux Linux964cbb198f9c46c2b2358cd1faffc04c1e8248cfVendor (CNA)
azl3 kernel 6.6.104.2-4 on Azure Linux 3.06.6.112.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:linux6.1.153-1 · 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.

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

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

Weakness class (CWE)

CWE-416 · Use After Free

CVSS vector

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

nvd-primary

Root cause

After a memory region is freed, another reference pointing to it is still used. By then, the same region may have been allocated for different data.

The bug in code

The whole CWE-416 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

c
free(dev->buf);/* ... another thread is still running ... */process(dev->buf);

Fixed

c
lock(&dev->lock);free(dev->buf);dev->buf = NULL;unlock(&dev->lock);

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. SSVC exploitation— → none
  2. Fix✗ → ✓

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

References

Show all references (11 more)

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

All records