CVE-2025-21969: Bluetooth: L2CAP: Fix slab-use-after-free Read in l2cap_send_cmd
CSIRTS triage
- What
- A use-after-free vulnerability in the Bluetooth L2CAP layer allows reading from freed memory during command transmission.
- Who is affected
- Systems with Bluetooth enabled and L2CAP protocol in use across affected kernel versions.
- Urgency
- High severity with memory corruption risk; immediate patching recommended despite no current exploitation reports.
- Action
- Update to a patched Linux kernel version that fixes the l2cap_send_cmd use-after-free condition.
AI-assisted analysis generated from the source advisory — verify against the original.
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Details
Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21969
Exploitation outlook
EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.
- Low exploitation riskCVE-2025-219690.22% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 12% of all EPSS-scored CVEs.
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2025-21969 | coverage & exploitation status | NVD · CVE.org |
Recent advisories for Bluetooth
A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.
- medium[UPDATE] [medium] Linux Kernel (Bluetooth): Multiple vulnerabilitiescert-bund · 2026-08-06
- mediumCVE-2026-64406: Bluetooth: fix UAF in bt_accept_dequeue()msrc · 2026-08-06
- mediumCVE-2024-56591: Bluetooth: hci_conn: Use disable_delayed_work_syncmsrc · 2026-08-06
- highCVE-2026-64557: Bluetooth: L2CAP: Fix use-after-free in l2cap_sock_new_connection_cb()msrc · 2026-08-06
- mediumCVE-2026-64408: Bluetooth: bnep: pin L2CAP connection during netdev registrationmsrc · 2026-08-06
- highCVE-2026-64471: Bluetooth: btusb: fix use-after-free on registration failuremsrc · 2026-08-06
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