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VulnerabilityPublished Updated

CVE-2026-63976: Linux kernel · Bluetooth: l2cap: clear chan->ident on ECRED reconfiguration success

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 8.8 High · fixed in f39049304ba655ffcbb92edbdf8c51a1f1210bed : patch Linux kernel soon.

Data as of 26 Oct 2026, 17:30 UTC

CVSS 3.1 base score
8.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.5% chance of exploitation in 30 days – higher than 46% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact
Total control over the software or total information disclosure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in f39049304ba655ffcbb92edbdf8c51a1f1210bed, cc2b4f749de09975bfa06e58bbbad2f6acd4c79c, c2afd2613fda90107c5e2fe8e855627451749c78 +5
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 19 Jul 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ 15f02b91056253e8cdc592888f431da0731337b8, < f39049304ba655ffcbb92edbdf8c51a1f1210bed
Fixed in
  • f39049304ba655ffcbb92edbdf8c51a1f1210bed
LinuxLinuxAffected
  • ≥ 15f02b91056253e8cdc592888f431da0731337b8, < cc2b4f749de09975bfa06e58bbbad2f6acd4c79c
Fixed in
  • cc2b4f749de09975bfa06e58bbbad2f6acd4c79c
LinuxLinuxAffected
  • ≥ 15f02b91056253e8cdc592888f431da0731337b8, < c2afd2613fda90107c5e2fe8e855627451749c78
Fixed in
  • c2afd2613fda90107c5e2fe8e855627451749c78
LinuxLinuxAffected
  • ≥ 15f02b91056253e8cdc592888f431da0731337b8, < ae0152d77d101c920769934fb102b18de0c6f526
Fixed in
  • ae0152d77d101c920769934fb102b18de0c6f526
LinuxLinuxAffected
  • ≥ 15f02b91056253e8cdc592888f431da0731337b8, < 59f5ecf6ad5c4db6ae81965a96156954a3b0d89a
Fixed in
  • 59f5ecf6ad5c4db6ae81965a96156954a3b0d89a
LinuxLinuxAffected
  • ≥ 15f02b91056253e8cdc592888f431da0731337b8, < 8e7977afaef37c6bd2b2654f1bce6ab40d471147
Fixed in
  • 8e7977afaef37c6bd2b2654f1bce6ab40d471147

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).

References

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