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CVE-2026-82388VulnerabilityPublished Updated

Zephyr: bt_hfp_hf_connect()

Affects zephyrSource GCVE Database

0
Authoritative record:CVE-2026-82388· Medium 5.3

Not known to be exploited · CVSS 5.3 Medium.

Data as of 28 Oct 2026, 22:28 UTC

CVSS 3.1 base score
5.3Medium
How severe the flaw is on the 0–10 CVSS scale.
CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 26 Oct 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Affected software

ProductAffectedFixed in
Ubuntu 26.10zephyrpkg:deb/ubuntu/zephyr?arch=source&distro=stonkingOther threatsAffected
  • =3.1.2-4
Fixed in–
Ubuntu 26.04 LTSzephyrpkg:deb/ubuntu/zephyr?arch=source&distro=resoluteOther threatsAffected
  • =3.1.2-1.1build1
  • =3.1.2-4
Fixed in–
Ubuntu 24.04 LTSzephyrpkg:deb/ubuntu/zephyr?arch=source&distro=nobleOther threatsAffected
  • =3.1.2-1.1
  • =3.1.2-1.1build1
Fixed in–
Ubuntu 22.04 LTSzephyrpkg:deb/ubuntu/zephyr?arch=source&distro=jammyOther threatsAffected
  • =3.1.2-1build3
Fixed in–
Ubuntu 20.04 LTSzephyrpkg:deb/ubuntu/zephyr?arch=source&distro=focalOther threatsAffected
  • =3.1.2-1build3
Fixed in–
Ubuntu 18.04 LTSzephyrpkg:deb/ubuntu/zephyr?arch=source&distro=bionicOther threatsAffected
  • =3.1.2-1build1
  • =3.1.2-1build2
Fixed in–

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Description

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.

References

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