CVE-2026-99239High· 7.8▾ TwilightIn the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: refuse __l2cap_chan_add if chan already has conn l2cap_chan may be linked to l2cap_conn at most once. This is assumed in several places, eg l2cap_cha…
▾ Twilight zone — High severity, or a signal on a lesser flaw
impact 42.9 · likelihood 0 · exploitation 0
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Exploit-prediction probability, daily snapshots since Nov 5.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via CVEORG
Last analysed / modified upstream
0.1%
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: L2CAP: refuse __l2cap_chan_add if chan already has conn
l2cap_chan may be linked to l2cap_conn at most once. This is assumed in several places, eg l2cap_chan_del cleanup.
There is a TOCTOU race where the invariant is violated:
[Task 1] [Task 2]
l2cap_chan_connect l2cap_sock_bind
l2cap_chan_lock lock_sock
l2cap_state_change if (sk->sk_state != BT_OPEN)
chan->state = BT_CONNECT
l2cap_sock_state_change_cb chan->state = BT_BOUND
sk->sk_state = BT_BOUND
lock_sock <------------------ release_sock
sk->sk_state = BT_CONNECT
l2cap_sock_connect() does not check sk->sk_state, so since chan->state is now BT_BOUND, subsequent connect() ends up with second __l2cap_chan_add.
Explicitly document and check the invariant in __l2cap_chan_add with WARN_ON_ONCE. The only callsite where it could be hit is l2cap_chan_connect, so add pre-check there to avoid relying on chan->state. chan->state read/write is not properly guarded currently so there can be other TOCTOUC problems.
Add l2cap_lock_chan in l2cap_sock_bind() to guard chan->state write.
Linux >= 8f90405a4a6f1f1880dc07996b47bf57c712bd8a < 85cc289eb08afa975375f838187369e68b429ee0Linux >= 32d783cafb46ff3ca58e6f9fd62c9c5f35eaf26b < 820579652b24ce277e0097cd65b42bd9b7b8bf07Linux >= 8922c7940bae9ce4b1736dddb6362370793835c2 < e618d928ec7f88cbeadfa3542adcac40f474e629Linux >= 91047a4396a8b1857a6f712a90cf33ec0012b189 < fabaff1c59ff2cc89cb7e5bd0186a5e15f0c73b2Linux >= 0b0e2bf39cf99e458d991b9df253727e036a7d7d < 52fe88e4ef87311eee32b45c65603e7c69e75e7dLinux >= d3b739db5dc6f688a60d56da872fabaf65246032 < 10c705dd706aa93164ba41f2566f15206d6c178eLinux >= b66774b48dd98f07254951f74ea6f513efe7ff8b < 73820561d8cbfd3364a29b8fa77f1707f26029daLinux >= b66774b48dd98f07254951f74ea6f513efe7ff8b < d3afd7803f9bc2a8c4270199497b60158b2fc647Linux >= b66774b48dd98f07254951f74ea6f513efe7ff8b < 86b55991d3cd690e73c5ef8d20b75ae4905b357aLinux 50c38d9f42a529691e4e67ea9cedf4f0bfc8d277Linux >= 5.10.265 < 5.10.273Linux >= 5.15.216 < 5.15.224Linux >= 6.1.183 < 6.1.191Linux >= 6.6.145 < 6.6.161Linux >= 6.12.97 < 6.12.115Linux >= 6.18.39 < 6.18.60Linux >= 7.1.4 < 7.2Linux 7.2Refer to the linked advisories for vendor-supplied fixes and affected version ranges.
Connected by shared product, vendor, weakness, or advisory.
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