CVE-2026-19739
- Source
- https://cve.org/CVERecord?id=CVE-2026-19739
- Import Source
- https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-19739.json
- JSON Data
- https://api.osv.dev/v1/vulns/CVE-2026-19739
- Aliases
-
- GHSA-84v8-vgp5-4vc9
- Published
- 2026-10-11T17:15:06Z
- Modified
- 2026-10-13T07:01:34Z
- Severity
-
- 6.5 (Medium) CVSS_V3 - CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H CVSS Calculator
- Summary
- Bluetooth LE controller leaks a retained RX node when an unexpected LL Control PDU arrives during a Connection Update
- Details
-
The Bluetooth Link Layer control procedure code in subsys/bluetooth/controller/ll_sw/ull_llcp_conn_upd.c retains the received RX node while a Connection Update / Connection Parameter procedure waits for its instant, so the node can later carry the host notification (llcp_rx_node_retain(), which marks it NODE_RX_TYPE_RETAIN and thereby suppresses the normal recycling in ull.c). The default: arm of llcp_rp_cu_rx() and llcp_lp_cu_rx() — the "invalid PDU, terminate the connection" path — completed the procedure without releasing that retained node. llcp_rr_check_done() then dequeued and freed the procedure context with ctx->node_ref.rx still pointing at the retained node, dropping the last reference to it.
A peer device in radio range can reach this without pairing, bonding, or encryption. Against a peripheral, the peer sends a well-formed LL_CONNECTION_UPDATE_IND with an instant a few connection events in the future (the node is retained and the procedure enters RP_CU_STATE_WAIT_INSTANT), then, before the instant is reached, sends any other LL Control PDU such as LL_LENGTH_REQ. ull_cp_rx() routes that PDU into the active remote Connection Update procedure, which takes the invalid-PDU path. The central role is reachable symmetrically after accepting an LL_CONNECTION_PARAM_REQ, and the local-procedure variant is reachable with LL_REJECT_IND.
With CONFIG_BT_CTLR_ASSERT_DEBUG enabled (its default), the resulting state violates the invariant asserted in llcp_rr_check_done(), so the two-PDU sequence produces an immediate fatal error in the controller. With those asserts disabled, each occurrence permanently loses one node from the controller's small fixed RX pool (sized from CONFIG_BT_CTLR_RX_BUFFERS, which defaults to 1); repeating the sequence across reconnections exhausts the pool, after which the link-layer receive path operates on a NULL node. The impact is an unauthenticated, remotely triggerable denial of service persisting until reboot; there is no memory-disclosure or memory-corruption consequence, since the leaked node simply becomes unreachable.
- Database specific
{ "cna_assigner": "zephyr", "cwe_ids": [ "CWE-401", "CWE-459", "CWE-617", "CWE-772" ], "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/19xxx/CVE-2026-19739.json", "unresolved_ranges": [ { "extracted_events": [ { "introduced": "3.4.0" }, { "fixed": "4.5.0" } ], "source": "AFFECTED_FIELD" } ] }- References
-
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/19xxx/CVE-2026-19739.json
- https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-84v8-vgp5-4vc9
- https://nvd.nist.gov/vuln/detail/CVE-2026-19739
- https://github.com/zephyrproject-rtos/zephyr/commit/7b600129faaba8bb26dd5cb3e8f17ed1cb41ea7f
- https://github.com/zephyrproject-rtos/zephyr
Affected packages
Git / github.com/zephyrproject-rtos/zephyr
Affected versions
v1.*
v2.*
v3.*
v4.*
zephyr-v1.*
zephyr-v2.*
zephyr-v3.*
Database specific
source
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-19739.json"
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vanir_signatures_modified
"2026-10-13T07:01:34Z"