CVE-2026-63976: Linux kernel · Bluetooth: l2cap: clear chan->ident on ECRED reconfiguration success
Affects Linux kernelSource CVE Database V5
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
- 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:HExploitation evidence
Disclosed: evidence found.
CVE published 19 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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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
- git.kernel.org/stable/c/59f5ecf6ad5c4db6ae81965a96156954a3b0d89a (opens in a new tab)
- git.kernel.org/stable/c/ae0152d77d101c920769934fb102b18de0c6f526 (opens in a new tab)
- git.kernel.org/stable/c/c2afd2613fda90107c5e2fe8e855627451749c78 (opens in a new tab)
- git.kernel.org/stable/c/cc2b4f749de09975bfa06e58bbbad2f6acd4c79c (opens in a new tab)
- git.kernel.org/stable/c/3b5b5f423b4fd23404a393bda8adba3cd6f74ef1 (opens in a new tab)
- git.kernel.org/stable/c/f39049304ba655ffcbb92edbdf8c51a1f1210bed (opens in a new tab)
- git.kernel.org/stable/c/8e7977afaef37c6bd2b2654f1bce6ab40d471147 (opens in a new tab)
- git.kernel.org/stable/c/00e1950716c6ed67d74777b2db286b0fa23b4be9 (opens in a new tab)