CVE-2026-31772Bluetooth: hci_sync: fix stack buffer overflow in hci_le_big_create_sync
- 7.8HighCVSS base score
- 0.14%Exploitation in 30 daysEPSS · top 96% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_sync: fix stack buffer overflow in hci_le_big_create_sync hci_le_big_create_sync() uses DEFINE_FLEX to allocate a struct hci_cp_le_big_create_sync on the stack with room for 0x11 (17) BIS entries. However, conn->num_bis can hold up to HCI_MAX_ISO_BIS (31) entries — validated against ISO_MAX_NUM_BIS (0x1f) in the caller hci_conn_big_create_sync(). When conn->num_bis is between 18 and 31, the memcpy that copies conn->bis into cp->bis writes up to 14 bytes past the stack buffer, corrupting adjacent stack memory. This is trivially reproducible: binding an ISO socket with bc_num_bis = ISO_MAX_NUM_BIS (31) and calling listen() will eventually trigger hci_le_big_create_sync() from the HCI command sync worker, causing a KASAN-detectable stack-out-of-bounds write: BUG: KASAN: stack-out-of-bounds in hci_le_big_create_sync+0x256/0x3b0 Write of size 31 at addr ffffc90000487b48 by task kworker/u9:0/71 Fix this by changing the DEFINE_FLEX count from the incorrect 0x11 to HCI_MAX_ISO_BIS, which matches the maximum number of BIS entries that conn->bis can actually carry.
Timeline
ID reserved
By Linux
- 53 days later
· 53 days later
Published
- 6 months later
· 6 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| LinuxCNA (assigner) | 3.1 | High7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| NVDNVD · Modified | 3.1 | High7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 0.14% · top 96% of all CVEs (13 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.8.
Affected products
- affected 91d19383b7ed035e22165ae5c836e50bb9f95fbe – < f5d446624345d309e7a4a1b27ea9f028d6a8c5d9
- affected 42ecf1947135110ea08abeaca39741636f9a2285 – < aba0aea354015794e8312dd7efe726967e58aefe
- affected 42ecf1947135110ea08abeaca39741636f9a2285 – < eaf32002ca7b1ba51c9f140991fd9febe6de79f0
- affected 42ecf1947135110ea08abeaca39741636f9a2285 – < bc39a094730ce062fa034a529c93147c096cb488
- affected 8958e1cee4e2eac1a5b825caa4dd96ce9ed975dd
- affected 6.12.2 – < 6.12.81
- affected 6.11.11 – < 6.12
- affected 6.13
- unaffected < 6.13
- unaffected 6.12.81 – ≤ 6.12.*
- unaffected 6.18.22 – ≤ 6.18.*
- unaffected 6.19.12 – ≤ 6.19.*
- unaffected 7.0 – ≤ *
References
References4
- https://git.kernel.org/stable/c/f5d446624345d309e7a4a1b27ea9f028d6a8c5d9 (opens in a new tab)
- https://git.kernel.org/stable/c/aba0aea354015794e8312dd7efe726967e58aefe (opens in a new tab)
- https://git.kernel.org/stable/c/eaf32002ca7b1ba51c9f140991fd9febe6de79f0 (opens in a new tab)
- https://git.kernel.org/stable/c/bc39a094730ce062fa034a529c93147c096cb488 (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-26585 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-31772)Record last updated .