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Vulnerabilities

Vulnerability · CVE-2026-87040

Bluetooth LE Controller accepts received PDUs whose length field exceeds the configured maximum receive length, causing out-of-bounds read and write

Published Nov 4, 2026 · catalog updated Nov 4, 2026 · Bluetooth LE Controller accepts

Last checked Nov 7, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2026-87040. EPSS is 0.29%. Act only if a listed version of Bluetooth LE Controller accepts is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (Bluetooth LE Controller accepts).
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
High8.3
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.29%
Remediation
Advisory link
Affected products
vendor zephyrproject zephyr

The nRF link-layer receive paths of the open-source Bluetooth LE Controller did not validate the on-air LENGTH field of a received PDU against the maximum receive length that was used to program the radio. isr_rx_pdu() in subsys/bluetooth/controller/ll_sw/nordic/lll/lll_conn.c enqueued any non-empty data PDU after only the sequence-number and (for encrypted links) MIC checks, and the corresponding isr_rx() handlers in lll_central_iso.c, lll_peripheral_iso.c, lll_sync_iso.c and lll_scan_aux.c did the same for ISO and extended-advertising PDUs. The nRF radio stores the received header verbatim and truncates only the payload at PCNF1.MAXLEN, so a frame declaring more octets than were configured leaves a node buffer whose len field describes more data than the buffer holds. An attacker within radio range that can emit a hand-crafted link-layer PDU — for a connection, any peer that establishes an unencrypted LE connection to a connectable advertiser; for CONFIG_BT_CTLR_SYNC_ISO, any broadcaster the device is synchronised to — can set the length byte up to 255 while the controller has programmed a much smaller maximum (lll->dle.eff.max_rx_octets, which is 27 until a Data Length Update, or the negotiated cis_lll->rx.max_pdu). No pairing, authentication or user interaction is required. On encrypted links the CCM MIC check normally rejects such a frame first, so the exposure is on unencrypted traffic, which is why the added check is placed after decryption. The unchecked length reaches hci_acl_encode() in subsys/bluetooth/controller/hci/hci.c, which performs net_buf_add(buf, pdu_data->len) followed by a memcpy() of that many bytes out of the node_rx pool element. Because CONFIG_BT_CTLR_DATA_LENGTH_MAX and CONFIG_BT_BUF_ACL_RX_SIZE both default to 27, this is an out-of-bounds read of up to roughly 228 bytes past the received PDU and a corresponding out-of-bounds write past the HCI ACL buffer into neighbouring buffers of the same pool; the tailroom test in net_buf_simple_add()

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

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  • vendor zephyrproject zephyrversion unspecified

How to fix CVE-2026-87040

  • No stored fix

    No vendor fix text is stored. Use the linked advisory before you change production.

  • Version check

    No version range is stored, so an installed version cannot be checked on this page.

  • Advisory

    Open the cve_org record and follow its fix.

  • Official advisories

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-87040. EPSS is 0.29%. Act only if a listed version of Bluetooth LE Controller accepts is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-120: Classic Buffer Overflow; CWE-787: Out-of-bounds Write. EPSS 0.29%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Nov 4, 2026 · Tenable CVE Database

    Detected

    The nRF link-layer receive paths of the open-source Bluetooth LE Controller did not validate the on-air LENGTH field of a received PDU against the maximum receive length that was used to program the radio. isr_rx_pdu() in subsys/bluetooth/controller/ll_sw/nordic/lll/lll_conn.c enqueued any non-empty data PDU after only the sequence-number and (for encrypted links) MIC checks, and the corresponding

  2. Nov 4, 2026 · CVE.org

    Updated

    The nRF link-layer receive paths of the open-source Bluetooth LE Controller did not validate the on-air LENGTH field of a received PDU against the maximum receive length that was used to program the radio. isr_rx_pdu() in subsys/bluetooth/controller/ll_sw/nordic/lll/lll_conn.c enqueued any non-empty data PDU after only the sequence-number and (for encrypted links) MIC checks, and the corresponding

Sources

  • CVE.orgVulnerability recordCVE-2026-87040

    The nRF link-layer receive paths of the open-source Bluetooth LE Controller did not validate the on-air LENGTH field of a received PDU against the maximum receive length that was used to program the radio. isr_rx_pdu() in subsys/bluetooth/controller/ll_sw/nordic/lll/lll_conn.c en

    cve.org
  • Tenable CVE DatabaseVulnerability recordCVE-2026-87040

    The nRF link-layer receive paths of the open-source Bluetooth LE Controller did not validate the on-air LENGTH field of a received PDU against the maximum receive length that was used to program the radio. isr_rx_pdu() in subsys/bluetooth/controller/ll_sw/nordic/lll/lll_conn.c enqueued any non-empty data PDU after only the sequence-number and (for encrypted links) MIC checks, and the corresponding

    tenable.com

References

Freshness

Last verified in this catalog Nov 7, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • CVE.orgNov 5, 2026
  • Tenable CVE DatabaseNov 4, 2026