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CVE-2026-63976

HIGHCVSS 8.8/10EPSS 0.44%

Last modified

CVE-2026-63976 is a high-severity vulnerability rated 8.8/10 on the CVSS scale. In the Linux kernel, the following vulnerability has been resolved: Bluetooth: l2cap: clear chan->ident on ECRED reconfiguration success l2cap_ecred_reconf_rsp() returns early on success without clearing chan->ident. Every other L2CAP response handler (l2cap_ecred_conn_rsp, l2cap_le_connect_rsp, l2cap_config_rsp) clears chan->ident after a successful transaction to prevent the channel from matching subsequent responses with the recycled ident value. A remote attacker that completed a reconfiguration as the peer can replay a failure response with the stale ident, causing the kernel to match and destroy the already-established channel via l2cap_chan_del(chan, ECONNRESET). Clear chan->ident for all matching channels on success, and harden the failure path by using l2cap_chan_hold_unless_zero() consistent with other L2CAP handlers (l2cap_le_command_rej, __l2cap_get_chan_by_ident).. EPSS estimates a 0.44% chance of exploitation in the next 30 days.

Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: l2cap: clear chan->ident on ECRED reconfiguration success l2cap_ecred_reconf_rsp() returns early on success without clearing chan->ident. Every other L2CAP response handler (l2cap_ecred_conn_rsp, l2cap_le_connect_rsp, l2cap_config_rsp) clears chan->ident after a successful transaction to prevent the channel from matching subsequent responses with the recycled ident value. A remote attacker that completed a reconfiguration as the peer can replay a failure response with the stale ident, causing the kernel to match and destroy the already-established channel via l2cap_chan_del(chan, ECONNRESET). Clear chan->ident for all matching channels on success, and harden the failure path by using l2cap_chan_hold_unless_zero() consistent with other L2CAP handlers (l2cap_le_command_rej, __l2cap_get_chan_by_ident).

Metrics

CVSS 3.1
8.8/10

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

EPSS Probability
0.44%

36.4th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

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

VendorProductVersions
LinuxLinux>= 15f02b91056253e8cdc592888f431da0731337b8, < 59f5ecf6ad5c4db6ae81965a96156954a3b0d89a; >= 15f02b91056253e8cdc592888f431da0731337b8, < ae0152d77d101c920769934fb102b18de0c6f526; >= 15f02b91056253e8cdc592888f431da0731337b8, < c2afd2613fda90107c5e2fe8e855627451749c78; >= 15f02b91056253e8cdc592888f431da0731337b8, < cc2b4f749de09975bfa06e58bbbad2f6acd4c79c; >= 15f02b91056253e8cdc592888f431da0731337b8, < 3b5b5f423b4fd23404a393bda8adba3cd6f74ef1; >= 15f02b91056253e8cdc592888f431da0731337b8, < f39049304ba655ffcbb92edbdf8c51a1f1210bed; >= 15f02b91056253e8cdc592888f431da0731337b8, < 8e7977afaef37c6bd2b2654f1bce6ab40d471147; >= 15f02b91056253e8cdc592888f431da0731337b8, < 00e1950716c6ed67d74777b2db286b0fa23b4be9
LinuxLinux5.7

References

Timeline

Published
Last Modified
Status
Awaiting Analysis

Frequently Asked Questions

What is CVE-2026-63976?
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: l2cap: clear chan->ident on ECRED reconfiguration success l2cap_ecred_reconf_rsp() returns early on success without clearing chan->ident. Every other L2CAP response handler (l2cap_ecred_conn_rsp, l2cap_le_connect_rsp, l2cap_config_rsp) clears chan->ident after a successful transaction to prevent the channel from matching subsequent responses with the recycled ident value. A remote attacker that completed a reconfiguration as the peer can replay a failure response with the stale ident, causing the kernel to match and destroy the already-established channel via l2cap_chan_del(chan, ECONNRESET). Clear chan->ident for all matching channels on success, and harden the failure path by using l2cap_chan_hold_unless_zero() consistent with other L2CAP handlers (l2cap_le_command_rej, __l2cap_get_chan_by_ident).
How severe is CVE-2026-63976?
CVE-2026-63976 has a CVSS score of 8.8/10 (HIGH severity). The EPSS model estimates a 0.44% probability of exploitation in the next 30 days.
How do I fix CVE-2026-63976?
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