Skip to content
Noroxi
CVE.org (no NVD analysis yet)· CNA zephyr

CVE-2026-82388: Use of a released HFP HF object after a failed RFCOMM connect in the Bluetooth Classic host

MediumCVSS 5.3 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 21/100)

  • 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: 0.20% (FIRST EPSS).
  • Someone on the same network segment can trigger it. No account or password is required. No user action is required. Special conditions such as timing or configuration are required.
  • Fixed version: zephyrproject zephyr 4.5.0.

Low priority for now. Upgrade to zephyrproject zephyr 4.5.0 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

bt_hfp_hf_connect() in subsys/bluetooth/host/classic/hfp_hf.c allocates the per-connection HFP Hands-Free object with hfp_hf_create(), which starts an SDP discovery by passing the object's embedded hf->sdp_param to bt_sdp_discover(). That call links the caller-owned parameter block into the SDP client's request list (session->reqs in subsys/bluetooth/host/classic/sdp.c). If the subsequent bt_rfcomm_dlc_connect() then failed, the affected code wiped the entire object with (void)memset(new_hf, 0, sizeof(*new_hf)) while that discovery was still outstanding, zeroing the sys_snode_t _node that is still linked in the SDP client's list along with the request's func, uuid and pool pointers, and zeroing the hf->slc_work work item that may already be queued on the system workqueue. The discovery could not be retracted instead: bt_sdp_discover_cancel() is declared in include/zephyr/bluetooth/classic/sdp.h but has no implementation. The failing branch is reachable with peer-supplied input. The documented use of bt_hfp_hf_connect() is to pass the RFCOMM channel read out of the remote Audio Gateway's SDP record; neither bt_sdp_get_proto_param() nor bt_hfp_hf_connect() range-checks that value, so a remote device advertising an HFP AG record with an RFCOMM channel outside 1-30 makes bt_rfcomm_dlc_connect() return -EINVAL and drives the local device into the wipe. The same branch is reached without any application misuse when the remote peer controls connection timing, for example when the RFCOMM session is in BT_RFCOMM_STATE_DISCONNECTING or the ACL is dropped between object creation and the RFCOMM call. Once the object has been wiped, the Bluetooth host continues to use it: sdp_client_alloc_buf() dereferences session->param->pool, which is now NULL, and the SDP receive paths call session->param->func() through a null function pointer, neither of which is NULL-checked. Because the wipe also clears hf->acl, the pool slot is considered free and a retry or an incoming HFP connection re-appends the same still-linked list node, turning session->reqs into a self-referential list that the host's list walkers never leave. The result is a fault or an unrecoverable hang in the Bluetooth host thread; the stray indirect call is through an all-zero pointer whose target the attacker does not control, so the practical impact is denial of service. The fix keeps the object allocated and marks it with a new BT_HFP_HF_FLAG_RELEASING flag, letting bt_hfp_hf_discover_cb() release it once the discovery completes instead of destroying it under the SDP client. Only builds with CONFIG_BT_CLASSIC and CONFIG_BT_HFP_HF enabled are affected.

Published
Oct 26, 2026
Updated
Oct 26, 2026
EPSS
0.2% · 11th percentile

Report tools

JSON

Action score

21

Monitor

Low priority for now.

CVSS
21 / 40 · 5.3 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · zephyr
5.3
NVD has not scored this yet; the score shown is the CNA’s.

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.

Follow CVE-2026-82388

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

One daily email digest (06:00 UTC); connect a webhook for KEV listings and weaponized exploits every 10 minutes on paid plans, on the hour on the free plan.

Your free account also gets you

  • CVE alerts: add the products and versions you run, get the new CVEs that affect them
  • Uptime monitoring: 1 site, instant email when it goes down
  • Add your domain: subdomains and takeover risk scanned every week (1 domain)
  • 10 scans an hour on the security tools, at most 30 a day (3 a day without an account), an API key and MCP
  • All your scans in one panel: findings, what changed in the last scan, a report per domain or per client (PDF, share link)
All free tools

Sign up with email · Have an account? Sign in

Free account, no card. Unfollow any time.

Don't want an account? Get "Exploited this week" by email every MondayDon't want an account? RSS feed for zephyrproject records
Is your version affected? Check it

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.

We use this product, ask for help

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 (zephyr). Independent of NVD's CPE analysis and usually ahead of it.

  • zephyrproject zephyr

    • 4.4.0 and later · before 4.5.0affected · semver

Same product

zephyrproject: all records

Other highest-scoring records for the same primary product.

  • CVE-2023-4260Potential off-by-one buffer overflow vulnerability in the Zephyr FS subsystem
    40Plan
  • CVE-2021-3625Buffer overflow in Zephyr USB DFU DNLOAD
    40Plan
  • CVE-2020-10071Insufficient publish message length validation in MQTT
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-81038Oct 26, 2026 · Bluetooth OTS server discloses uninitialized stack memory in failed Calculate Checksum responses
    28Monitor
  • ← EarlierCVE-2026-81039Oct 26, 2026 · Bluetooth Host connection reservation leak when multiple connectable advertising sets share an identity
    17Monitor
  • Later →CVE-2026-82389Oct 26, 2026 · Bluetooth Classic HFP AG wipes an object still linked in the SDP request list on connect failure, causing a NULL dereference
    26Monitor

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
zephyrproject zephyr4.5.0Vendor (CNA)

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. TodayNov 13, 2026+18 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.

Variant candidates

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

  • CVE-2026-850358 days apartUse-after-free via dynamically allocated message queue retained by the CAN RX filter
    35Monitor
  • CVE-2026-1236673 days apartUse-after-free freeing an armed dynamically-allocated k_timer in Zephyr userspace object disposal
    35Monitor
  • CVE-2026-799793 days apartStale TLB entries after demand-paging page-out let arm64 user threads access reused physical frames
    31Monitor
  • CVE-2026-10667106 days apartSMP use-after-free in Zephyr `CONFIG_USERSPACE` dynamic kernel-object tracking, reachable from unprivileged user threads
    31Monitor
  • CVE-2026-1993515 days apartUse-after-free of an L2CAP CoC channel object in the Zephyr Bluetooth host: RX work item is not cancelled on channel teardown
    30Monitor
  • CVE-2026-1068587 days apartUse-after-free of GATT subscribe params in Bluetooth host CCC-write response handler
    30Monitor

Not on record for this CVE: researcher credit · public bounty program.

Technical details

Attack conditions

  • Someone on the same network segment can trigger it.
  • No account or password is required.
  • No user action is required.
  • Special conditions such as timing or configuration are required.

If successful

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

Weakness class (CWE)

CWE-416 · Use After Free

CVSS vector

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

nvd-secondary

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. Exploit maturity— → none
  3. Fix✗ → ✓

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

References

Show all references (1 more)

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

All records