CVE-2026-19570: Out-of-bounds write in LE Audio Broadcast Sink when copying BASE subgroup metadata into the BASS receive state
Noroxi assessment
Priority: Monitor (action score 35/100)
- The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
- Probability of exploitation in the next 30 days: 0.29% (FIRST EPSS).
- Someone on the same network segment can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
- Fixed version: zephyrproject zephyr 4.5.0.
Low priority for now. Upgrade to zephyrproject zephyr 4.5.0 or later.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
The LE Audio Broadcast Sink in subsys/bluetooth/audio/bap_broadcast_sink.c copies subgroup metadata from a received Basic Audio Announcement (BASE) into the static Broadcast Audio Scan Service parameter structure mod_src_param without any bounds check. In base_subgroup_meta_cb() the destination element was selected as mod_src_param.subgroups[mod_src_param.num_subgroups] with no test against ARRAY_SIZE(mod_src_param.subgroups) (sized by CONFIG_BT_BAP_BASS_MAX_SUBGROUPS, default 1), and the metadata was copied with memcpy() using the raw on-air length returned by bt_bap_base_get_subgroup_codec_meta() into a metadata array sized by CONFIG_BT_AUDIO_CODEC_CFG_MAX_METADATA_SIZE (default 4). The BASE validator bt_bap_base_get_base_from_ad() only checks structural consistency and permits up to ~24 subgroups and metadata LTVs of ~240 octets. The defect is reached from the periodic advertising receive callback: pa_recv() → bt_data_parse() → pa_decode_base() → update_recv_state_base() → bt_bap_base_foreach_subgroup() → base_subgroup_meta_cb(). Every broadcast sink registers a scan-delegator receive state at creation (bt_bap_broadcast_sink_create() calls broadcast_sink_add_src()), and CONFIG_BT_BAP_BROADCAST_SINK depends on CONFIG_BT_BAP_SCAN_DELEGATOR, so the path is active in every broadcast-sink build once the device is periodic-advertising-synced. An attacker in radio range who operates a broadcast source the device syncs to — or who impersonates the advertiser address and SID of one already in use, periodic advertising data being unauthenticated — can change the BASE at will; each new BASE is re-parsed. A crafted BASE therefore writes attacker-chosen bytes past the end of a fixed static object in .bss: up to roughly 236 bytes for an oversized metadata LTV, plus whole struct bt_bap_bass_subgroup records for each subgroup beyond CONFIG_BT_BAP_BASS_MAX_SUBGROUPS. This is memory corruption of adjacent Bluetooth-audio state reachable with no pairing, bonding or GATT connection, with a potential for remote code execution in the Bluetooth RX thread; in addition, the unvalidated metadata_len is forwarded to bt_bap_scan_delegator_mod_src(), which neither clamps it nor rejects it, leading to a further copy into the receive state and to out-of-bounds memory being disclosed in the BASS receive-state notification sent to a connected Broadcast Assistant. The fix rejects a BASE carrying more subgroups than the receive state can hold (discarding the update entirely) and omits metadata that does not fit rather than copying it, and additionally honours the previously-ignored error return of the subgroup decode pass.
- Published
- Oct 9, 2026
- Updated
- Nov 4, 2026
- EPSS
- 0.2% · 22th percentile
- CWE
- CWE-120
Report tools
Action score
35
Low priority for now.
- CVSS
- 35 / 40 · 8.8 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.2%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- total
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · zephyr
- 8.8
- NVD has not scored this yet; the score shown is the CNA’s.
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- No public exploit code on record
- A fix has been released
If any of these changes, we'll tell you in the daily email digest.
Is your version affected? Check itNoroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
—
Versions reported by the vendor
Affected version ranges reported by the assigning authority (zephyr). Independent of NVD's CPE analysis and usually ahead of it.
zephyrproject zephyr
- 3.6.0 and later · before 4.5.0affected · semver
Same product
zephyrproject: all recordsOther highest-scoring records for the same primary product.
- CVE-2023-4260Potential off-by-one buffer overflow vulnerability in the Zephyr FS subsystem40Plan
- CVE-2021-3625Buffer overflow in Zephyr USB DFU DNLOAD40Plan
- CVE-2020-10071Insufficient publish message length validation in MQTT40Plan
Published before and after this one in the same product
- ← EarlierCVE-2026-19186Oct 7, 2026 · Integer underflow in IEEE 802.15.4 frame decryption leads to out-of-bounds read and write32Monitor
- ← EarlierCVE-2026-19569Oct 9, 2026 · Integer overflow in dynamic kernel object allocation allows user-mode threads to corrupt the kernel heap35Monitor
- Later →CVE-2026-19571Oct 9, 2026 · Race condition in ITE IT8xxx2 SHI host-command backend lets a second SPI request write an unvalidated length into the in-flight request buffer26Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| zephyrproject zephyr | 4.5.0 | Vendor (CNA) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
- Published
- Fix recorded+26 d
- TodayNov 13, 2026+35 d
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
- CVE-2026-8704026 days apartBluetooth LE Controller accepts received PDUs whose length field exceeds the configured maximum receive length, causing out-of-bounds read and write33Monitor
- CVE-2026-1679195 days apartnet: eswifi socket send payload length not bounded31Monitor
- CVE-2026-0849207 days apartcrypto: ATAES132A response length allows stack buffer overflow27Monitor
Not on record for this CVE: researcher credit · public bounty program.
Technical details
Attack conditions
- Someone on the same network segment can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- high · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- high · the service can be disrupted
- Attack vector
- Adjacent
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
CWE-120 · Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')CVSS vector
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
nvd-secondary
Root cause
When data is copied, the source length is not compared with the size of the destination buffer. Excess data overwrites adjacent memory.
The bug in code
The whole CWE-120 classA representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.
Vulnerable
char buf[256];
memcpy(buf, pkt->data, pkt->len);Fixed
char buf[256];
if (pkt->len > sizeof(buf)) {
return -EINVAL;
}
memcpy(buf, pkt->data, pkt->len);Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
- Buffer Overflow via Environment VariablesCAPEC-10likelihood: High · High
- Overflow BuffersCAPEC-100likelihood: High · Very High
- Client-side Injection-induced Buffer OverflowCAPEC-14likelihood: Medium · High
- Filter Failure through Buffer OverflowCAPEC-24likelihood: High · High
- MIME ConversionCAPEC-42likelihood: High · High
- Overflow Binary Resource FileCAPEC-44likelihood: High · Very High
- Buffer Overflow via Symbolic LinksCAPEC-45likelihood: High · High
- Overflow Variables and TagsCAPEC-46likelihood: High · High
ATT&CK techniques
—
Change log
- Fix✗ → ✓
- SSVC exploitation— → none
- Exploit maturity— → none
For records you follow, these changes also arrive as notifications. →
References
Show all references (1 more)Show less
Vendor advisories and official records. Exploit/PoC links are deliberately left out.