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CVE-2026-99239

Bluetooth: L2CAP: refuse __l2cap_chan_add if chan already has conn

High7.8
Published
Updated
Reserved
Assigned by
Linux

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.

Scores

CVSS scores of CVE-2026-99239, by who scored it
Scored byCVSSScoreVector
LinuxCNA (assigner)3.1High7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVDNVD · Received3.1High7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS (exploitation in 30 days)
Not scored

The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.8.

Affected products

  • Linux · Linux

    • affected 8f90405a4a6f1f1880dc07996b47bf57c712bd8a – < 85cc289eb08afa975375f838187369e68b429ee0
    • affected 32d783cafb46ff3ca58e6f9fd62c9c5f35eaf26b – < 820579652b24ce277e0097cd65b42bd9b7b8bf07
    • affected 8922c7940bae9ce4b1736dddb6362370793835c2 – < e618d928ec7f88cbeadfa3542adcac40f474e629
    • affected 91047a4396a8b1857a6f712a90cf33ec0012b189 – < fabaff1c59ff2cc89cb7e5bd0186a5e15f0c73b2
    • affected 0b0e2bf39cf99e458d991b9df253727e036a7d7d – < 52fe88e4ef87311eee32b45c65603e7c69e75e7d
    • affected d3b739db5dc6f688a60d56da872fabaf65246032 – < 10c705dd706aa93164ba41f2566f15206d6c178e
    • affected b66774b48dd98f07254951f74ea6f513efe7ff8b – < 73820561d8cbfd3364a29b8fa77f1707f26029da
    • affected b66774b48dd98f07254951f74ea6f513efe7ff8b – < d3afd7803f9bc2a8c4270199497b60158b2fc647
    • affected 50c38d9f42a529691e4e67ea9cedf4f0bfc8d277
    • affected 5.10.265 – < 5.10.273
    • affected 5.15.216 – < 5.15.224
    • affected 6.1.183 – < 6.1.191
    • affected 6.6.145 – < 6.6.161
    • affected 6.12.97 – < 6.12.115
    • affected 6.18.39 – < 6.18.60
    • affected 7.1.4 – < 7.2

  • Linux · Linux

    • affected 7.2
    • unaffected < 7.2
    • unaffected 5.10.273 – ≤ 5.10.*
    • unaffected 5.15.224 – ≤ 5.15.*
    • unaffected 6.1.191 – ≤ 6.1.*
    • unaffected 6.6.161 – ≤ 6.6.*
    • unaffected 6.12.115 – ≤ 6.12.*
    • unaffected 6.18.60 – ≤ 6.18.*
    • unaffected 7.2.14 – ≤ 7.2.*
    • unaffected 7.3.1 – ≤ 7.3.*

References (8)

Sources

The same CVE in the primary databases and aggregators, to check against.

Record last updated .