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CVE-2026-99239

HIGHCVSS 7.8/10EPSS 0.12%

Last modified

CVE-2026-99239 is a high-severity vulnerability rated 7.8/10 on the CVSS scale. 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. EPSS estimates a 0.12% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1
7.8/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Probability
0.12%

1.9th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= 8f90405a4a6f1f1880dc07996b47bf57c712bd8a, < 85cc289eb08afa975375f838187369e68b429ee0; >= 32d783cafb46ff3ca58e6f9fd62c9c5f35eaf26b, < 820579652b24ce277e0097cd65b42bd9b7b8bf07; >= 8922c7940bae9ce4b1736dddb6362370793835c2, < e618d928ec7f88cbeadfa3542adcac40f474e629; >= 91047a4396a8b1857a6f712a90cf33ec0012b189, < fabaff1c59ff2cc89cb7e5bd0186a5e15f0c73b2; >= 0b0e2bf39cf99e458d991b9df253727e036a7d7d, < 52fe88e4ef87311eee32b45c65603e7c69e75e7d; >= d3b739db5dc6f688a60d56da872fabaf65246032, < 10c705dd706aa93164ba41f2566f15206d6c178e; >= b66774b48dd98f07254951f74ea6f513efe7ff8b, < 73820561d8cbfd3364a29b8fa77f1707f26029da; >= b66774b48dd98f07254951f74ea6f513efe7ff8b, < d3afd7803f9bc2a8c4270199497b60158b2fc647; >= b66774b48dd98f07254951f74ea6f513efe7ff8b, < 86b55991d3cd690e73c5ef8d20b75ae4905b357a; 50c38d9f42a529691e4e67ea9cedf4f0bfc8d277; >= 5.10.265, < 5.10.273; >= 5.15.216, < 5.15.224; >= 6.1.183, < 6.1.191; >= 6.6.145, < 6.6.161; >= 6.12.97, < 6.12.115; >= 6.18.39, < 6.18.60; >= 7.1.4, < 7.2
LinuxLinux7.2

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-99239?
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 severe is CVE-2026-99239?
CVE-2026-99239 has a CVSS score of 7.8/10 (HIGH severity). The EPSS model estimates a 0.12% probability of exploitation in the next 30 days.
How do I fix CVE-2026-99239?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST