CVE-2026-19738
Medium · CVSS 6.5Published 2026-10-11
CVSS
6.5
Medium
EPSS
—
exploit probability
Active Exploit
No
not yet listed
What is CVE-2026-19738?
The Bluetooth Link Layer Control Procedure (LLCP) implementation for Connected Isochronous Stream (CIS) creation retains an RX node (ctx->node_ref.rx, marked NODE_RX_TYPE_RETAIN) so it can later be reused as the host notification — on the peripheral while awaiting the Host's reply to an LL_CIS_REQ, and on the central for the whole duration of a locally initiated CIS Create. In subsys/bluetooth/controller/ll_sw/ull_llcp_cc.c, the "invalid PDU received" paths of llcp_rp_cc_rx() and llcp_lp_cc_rx() terminated the connection and completed the procedure without releasing that retained node, breaking the invariant checked in llcp_lr_check_done() and llcp_rr_check_done() and orphaning the node's memory. A peer device within radio range can reach this with a single extra LL Control PDU on an unauthenticated, unencrypted ACL link. Against a peripheral, the attacker sends a valid LL_CIS_REQ and then, before the Host replies, any unrelated LL Control PDU (for example LL_VERSION_IND), which ull_cp_rx() routes into the active remote procedure. Against a central performing a CIS Create, a malicious peripheral answers with LL_UNKNOWN_RSP for CIS_REQ, which is dispatched into the active local procedure. No pairing, encryption or user interaction is required; the code is compiled in when CONFIG_BT_CTLR_PERIPHERAL_ISO or CONFIG_BT_CTLR_CENTRAL_ISO is enabled. In default builds (CONFIG_BT_CTLR_ASSERT_DEBUG is default y) the retained-node assertion fires immediately, producing a controller fatal error and, typically, a system reset from one injected PDU. With the development assertions disabled, each attempt permanently loses one node from the controller's small LL notification pool (LL_PDU_RX_CNT, 2 * CONFIG_BT_CTLR_LLCP_CONN) together with its memq_link_t; repeating the connect-attack-reconnect cycle exhausts the pool, after which notification allocation always fails, RX flow control stalls, and the non-disableable LL_ASSERT_ERR() in llcp_lp_cc_flush() faults. The impact is limited to availability — the leaked node is orphaned, never reused or double-freed — and recovery requires a reboot.
CVSS Score Explained
CVSS 6.5 is Medium severity. Exploitation usually requires some specific conditions (local access, user interaction, or a particular config). Still worth patching in your next maintenance window.
EPSS Exploitation Probability
No EPSS score yet — model needs more data on this CVE.
References & Patches
- ›https://github.com/zephyrproject-rtos/zephyr/commit/fde17f2c3de0118f3796c2a83958ee4ce4b5efd6
- ›https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-6mcj-5jw8-ff36
Track vulnerabilities for your stack
Tell us what tech you run — Node.js, Python, Java, nginx, whatever — and get a weekly email when new CVEs affect it.
Recent CVEs
- CVE-2026-104703Rejected reason: This CVE ID has been rejected or withdrawn by its CVE Numbering Authority.—
- CVE-2026-108770A weakness has been identified in Appwrite up to 2.3.0. This vulnerability affects the function PublicHostname of the file src/Appwrite/Platform/Modules/Avatars/Http/Screenshots/Get.php of the component Browser Screenshot Service. This manipulation of the argument url causes server-side request forgery. The attack can be initiated remotely. Upgrading to version 2.4.0 is able to resolve this issue. Patch name: 393255e7302ae5503331d45802e2eee01c6a47fe. You should upgrade the affected component.6.9
- CVE-2026-108772A security vulnerability has been detected in bleenco abstruse up to 2.1.0. This issue affects the function filepath.Join of the file server/api/worker/download_cache.go of the component Cache Endpoint. Such manipulation of the argument File leads to path traversal. The attack can be launched remotely. The exploit has been disclosed publicly and may be used. The vendor was contacted early about this disclosure but did not respond in any way.5.5
- CVE-2026-108773A vulnerability was detected in erzhongxmu JEEWMS up to 2026.09.27-W39. Impacted is the function docheck of the file src/main/java/com/zzjee/wm/controller/WmOmNoticeHController.java. Performing a manipulation of the argument goodscode results in sql injection. The attack may be initiated remotely. The exploit is now public and may be used. The vendor was contacted early about this disclosure but did not respond in any way.2.1
- CVE-2026-108769A security flaw has been discovered in zhayujie CowAgent up to 2.2.0. This affects an unknown part of the file Markdown.tsx of the component Markdown Rendering. The manipulation results in denial of service. It is possible to launch the attack remotely. The exploit has been released to the public and may be used for attacks. The vendor was contacted early about this disclosure but did not respond in any way.2.1
- CVE-2026-108978Heap-based buffer overflow vulnerability in Samsung Opensource rlottie allows Buffer Overflow via Environment Variables.
This issue affects rlottie: e57b094f03c39a751a1fded6f7d6c13f1ed95ec9.5.5