Zephyr: bt_iso_recv()
Affects zephyrSource GCVE Database
Not known to be exploited · CVSS 7.1 High.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 20% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 22 Jun 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.10zephyrpkg:deb/ubuntu/zephyr?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSzephyrpkg:deb/ubuntu/zephyr?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 25.10zephyrpkg:deb/ubuntu/zephyr?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSzephyrpkg:deb/ubuntu/zephyr?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu 22.04 LTSzephyrpkg:deb/ubuntu/zephyr?arch=source&distro=jammyOther threats | Affected
| Fixed in– |
Ubuntu 20.04 LTSzephyrpkg:deb/ubuntu/zephyr?arch=source&distro=focalOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
Description
bt_iso_recv() in subsys/bluetooth/host/iso.c pulled the ISO SDU header (4 bytes) or, when the timestamp flag is set, the timestamped SDU header (8 bytes) from the inbound HCI ISO Data buffer via net_buf_pull_mem() without first checking buf->len. The upstream hci_iso() handler enforces buf->len == the controller-declared ISO Data_Load length, so a malicious or buggy controller / adjacent BLE peer on an established CIS/BIS can present a first-fragment (BT_ISO_START) or single (BT_ISO_SINGLE) PDU shorter than the SDU header. Because net_buf_simple_pull_mem only guards length with __ASSERT_NO_MSG (compiled out when CONFIG_ASSERT is disabled, the production default), the pull underflows buf->len (uint16_t, e.g. 0 - 8 = 0xFFF8) and advances buf->data past valid data: the subsequent reads of hdr->slen and hdr->sn are out-of-bounds reads of adjacent pool memory. For the multi-fragment (START) case the corrupted buffer is retained as iso->rx, and a following CONT/END fragment's net_buf_tailroom() guard underflows to a near-SIZE_MAX value, defeating the bounds check and causing net_buf_add_mem() to memcpy attacker-supplied fragment data far past the RX pool buffer (out-of-bounds write). The flaw affects ISO receive builds (CONFIG_BT_ISO_RX, selected by the default-off LE Audio options BT_ISO_PERIPHERAL/BT_ISO_CENTRAL/BT_ISO_SYNC_RECEIVER) and has existed since the ISO subsystem was introduced (v2.6.0) through v4.4.0. The fix adds explicit buf->len < sizeof(ts_hdr) and buf->len < sizeof(hdr) checks that drop the buffer before pulling.