CVE-2026-11893
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Double free / use-after-free in Bouffalo Lab HCI driver send() error paths (hci_bflb)
rank 15 = 0 + 15 + 0 + 0 + 0
rank@v1 · backlog
Someone is already using it
CISA KEV catalog · public proof-of-concept · FIRST EPSS
EPSS 0.00158 · without this subject the record ranks 15
What it costs you if it fires
NVD CVSS base score, then the CNA's own
CVSS 5.9, from the CNA · without this subject the record ranks 0
It is getting worse, not staying still
FIRST EPSS series, rescorings and bad loads removed
no persisting rise in 365 days · without this subject the record ranks 15
How much of the world it touches
NVD CPE configurations
0 products in the CPE ranges · without this subject the record ranks 15
Someone else already set the date
CISA KEV remediation due date
no CISA due date · without this subject the record ranks 15
$5,660 = $4.99M incident cost x 0.7179585840212677 exposure x 0.00158 likelihood
udv@v1 · unaudited · wrong for you until you say what you run
$4.99M is the cost of a breach that happened, from IBM Cost of a Data Breach Report 2026, global average. It is not the value of any asset of yours. That average already covers breaches of every severity, so scaling it by exposure understates a partial-impact record. That is an assumption, not a measurement. Your own asset value goes in the decision record.
Hindsight · the state
Foresight · where to check next
This record is one instance of CWE-415, double free. The index holds 885 prior instances of this class, 6 KEV-listed. The nearest of its KEV-listed records are drawn beside this. taxonomy@v1
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Harm, if it fires from the vector and the weakness
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CISA KEV & Federal Remediation Deadline from the record and CISA
The fix, and how long it's been waiting.
Exploit Status & Known PoCs a ladder, not a score
Current rung: Nothing observed in held sources.
- RUNG 1Nothing observed in held sources
- RUNG 2Proof-of-concept published
- RUNG 3Exploited in the wild · CISA KEV listed
- RUNG 4Ransomware campaign use known
A rung lights from a row in the index, never from an assessment. "Held sources" is the true scope of the claim: this index reads the CVE record, NVD, CISA KEV, FIRST's EPSS and public proof-of-concept repositories, and it does not observe attacks.
Attack path
What it is stated by the CNA
The Bluetooth HCI driver for Bouffalo Lab on-chip BLE controllers (BL60x/BL70x/BL61x), bt_bflb_send() in drivers/bluetooth/hci/hci_bflb.c, violates the bt_hci_driver_api.send() buffer-ownership contract. That contract (documented at include/zephyr/drivers/bluetooth.h) requires the buffer reference to be consumed only on success; on error the caller still owns the reference and unrefs it. The driver instead routed all error paths through a shared label that unconditionally called net_buf_unref(buf) before returning the error code, consuming the buffer on failure as well. When send() returns an error, the host TX path (send_buf() in subsys/bluetooth/host/conn.c) unrefs the same buffer again, receipt
Read the rest of the CNA's description
believing it still owns it. This double-unref over-decrements the net_buf reference count. Because the buffer is a TX fragment whose destroy callback also decrements its still-queued parent buffer, the parent is freed prematurely while reachable on the connection TX queue, producing a use-after-free and corruption of the shared net_buf pool rather than a benign leak. The error conditions are on the host-to-controller transmit path (controller send failure, or an unsupported H:4 packet type), so they are not driven directly by attacker-supplied radio bytes; a remote/adjacent peer can influence them only indirectly, e.g. by inducing controller TX failures under heavy link load. The consequence when reached is BLE-stack denial of service (crash / pool corruption) with possible further memory corruption, bounded to devices using one of these Bouffalo Lab on-chip controllers.
NVD's analysis a second authority
- weakness
- CWE-415
- also scored by
- [email protected] 5.9 CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H
check it yourself github.com github.com receipt
Movement
Only one observation of this value is held, so there is no movement to show yet.
The full biography
The pattern, elsewhere
This record is one instance of CWE-415, double free. The index holds 885 prior instances of this class, 6 KEV-listed. The nearest of its KEV-listed records are drawn beside this. [email protected]
"Matches n of m" counts the attributes the two records can both be compared on: the CVSS metrics they share a version of, any weakness class beyond this one, and the vendor. fit-rules@v1
885 records in this class held. The six above are drawn from the ones CISA has listed as exploited, ranked by how much of the record matches this one. That is why every one of them is KEV-listed: the pool is, so the colour on those spokes says nothing the pool has not already said.
No curated product neighbourhood is held for this product, so the records above are the nearest this index can name. The neighbourhood table covers a small set of products and is extended by hand.
Siblings and hubs
Records related to this one
No record cites this identifier and it carries no alias. Its defect family is below.
Its defect family
zephyrproject zephyr
Of the 3 records in this family that state one, this holds the lowest EPSS percentile: 0.05303.
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Family membership: held values
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What usually comes next
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