CVE-2026-99239
Description
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.
How to fix
- Linux Linux85cc289eb08afa975375f838187369e68b429ee0, 820579652b24ce277e0097cd65b42bd9b7b8bf07, e618d928ec7f88cbeadfa3542adcac40f474e629, fabaff1c59ff2cc89cb7e5bd0186a5e15f0c73b2, 52fe88e4ef87311eee32b45c65603e7c69e75e7d, 10c705dd706aa93164ba41f2566f15206d6c178e, 73820561d8cbfd3364a29b8fa77f1707f26029da, d3afd7803f9bc2a8c4270199497b60158b2fc647, 86b55991d3cd690e73c5ef8d20b75ae4905b357a, 5.10.273, 5.15.224, 6.1.191, 6.6.161, 6.12.115, 6.18.60, 7.2 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| Linux Linux | 8f90405a4a6f1f1880dc07996b47bf57c712bd8a ≤ v < 85cc289eb08afa975375f838187369e68b429ee0, 32d783cafb46ff3ca58e6f9fd62c9c5f35eaf26b ≤ v < 820579652b24ce277e0097cd65b42bd9b7b8bf07, 8922c7940bae9ce4b1736dddb6362370793835c2 ≤ v < e618d928ec7f88cbeadfa3542adcac40f474e629, 91047a4396a8b1857a6f712a90cf33ec0012b189 ≤ v < fabaff1c59ff2cc89cb7e5bd0186a5e15f0c73b2, 0b0e2bf39cf99e458d991b9df253727e036a7d7d ≤ v < 52fe88e4ef87311eee32b45c65603e7c69e75e7d, d3b739db5dc6f688a60d56da872fabaf65246032 ≤ v < 10c705dd706aa93164ba41f2566f15206d6c178e, b66774b48dd98f07254951f74ea6f513efe7ff8b ≤ v < 73820561d8cbfd3364a29b8fa77f1707f26029da, b66774b48dd98f07254951f74ea6f513efe7ff8b ≤ v < d3afd7803f9bc2a8c4270199497b60158b2fc647, b66774b48dd98f07254951f74ea6f513efe7ff8b ≤ v < 86b55991d3cd690e73c5ef8d20b75ae4905b357a, 50c38d9f42a529691e4e67ea9cedf4f0bfc8d277, 5.10.265 ≤ v < 5.10.273, 5.15.216 ≤ v < 5.15.224, 6.1.183 ≤ v < 6.1.191, 6.6.145 ≤ v < 6.6.161, 6.12.97 ≤ v < 6.12.115, 6.18.39 ≤ v < 6.18.60, 7.1.4 ≤ v < 7.2, 7.2 | 85cc289eb08afa975375f838187369e68b429ee0, 820579652b24ce277e0097cd65b42bd9b7b8bf07, e618d928ec7f88cbeadfa3542adcac40f474e629, fabaff1c59ff2cc89cb7e5bd0186a5e15f0c73b2, 52fe88e4ef87311eee32b45c65603e7c69e75e7d, 10c705dd706aa93164ba41f2566f15206d6c178e, 73820561d8cbfd3364a29b8fa77f1707f26029da, d3afd7803f9bc2a8c4270199497b60158b2fc647, 86b55991d3cd690e73c5ef8d20b75ae4905b357a, 5.10.273, 5.15.224, 6.1.191, 6.6.161, 6.12.115, 6.18.60, 7.2 |
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