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VulnerabilityPublished Updated

CVE-2026-63945: Linux kernel · Bluetooth: ISO: serialize iso_sock_clear_timer with socket lock

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 7.8 High · fixed in d9cbf7144ec589a3f0cc91f74a1a1af2d2b14afa : patch Linux kernel soon.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 2% 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 d9cbf7144ec589a3f0cc91f74a1a1af2d2b14afa, bc08c15746f25f41dd0508b25780d1e84acbb2ef, 996c2104d0726a8fe584f85b3d6327197374a348 +3
CVSS:3.1/AV:L/AC:L/PR:L/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
  • ≥ ccf74f2390d60a2f9a75ef496d2564abb478f46a, < d9cbf7144ec589a3f0cc91f74a1a1af2d2b14afa
Fixed in
  • d9cbf7144ec589a3f0cc91f74a1a1af2d2b14afa
LinuxLinuxAffected
  • ≥ ccf74f2390d60a2f9a75ef496d2564abb478f46a, < bc08c15746f25f41dd0508b25780d1e84acbb2ef
Fixed in
  • bc08c15746f25f41dd0508b25780d1e84acbb2ef
LinuxLinuxAffected
  • ≥ ccf74f2390d60a2f9a75ef496d2564abb478f46a, < 996c2104d0726a8fe584f85b3d6327197374a348
Fixed in
  • 996c2104d0726a8fe584f85b3d6327197374a348
LinuxLinuxAffected
  • ≥ ccf74f2390d60a2f9a75ef496d2564abb478f46a, < 51cb9dcfdf9a1bccf312ab2ae4b62db629f7dcd5
Fixed in
  • 51cb9dcfdf9a1bccf312ab2ae4b62db629f7dcd5
LinuxLinuxAffected
  • ≥ ccf74f2390d60a2f9a75ef496d2564abb478f46a, < 35f68f36d9883d56dec21cf85f7556d4657fc393
Fixed in
  • 35f68f36d9883d56dec21cf85f7556d4657fc393
LinuxLinuxAffected
  • ≥ ccf74f2390d60a2f9a75ef496d2564abb478f46a, < 4b5f8e608749b7e8fa386c6e4301cf9272595859
Fixed in
  • 4b5f8e608749b7e8fa386c6e4301cf9272595859

Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: ISO: serialize iso_sock_clear_timer with socket lock iso_sock_close() calls iso_sock_clear_timer() before acquiring lock_sock(sk). iso_sock_clear_timer() reads iso_pi(sk)->conn twice without the socket lock held: if (!iso_pi(sk)->conn) return; cancel_delayed_work(&iso_pi(sk)->conn->timeout_work); Concurrently, iso_conn_del() executes under lock_sock(sk) and calls iso_chan_del(), which sets iso_pi(sk)->conn to NULL and may result in the final reference to the connection being dropped: CPU0 CPU1 ---- ---- iso_sock_clear_timer() if (conn != NULL) ... lock_sock(sk) iso_chan_del() iso_pi(sk)->conn = NULL cancel_delayed_work(conn) /* NULL deref or UAF */ iso_pi(sk)->conn is not stable across the unlock window, causing a NULL pointer dereference or use-after-free. Serialize iso_sock_clear_timer() with the socket lock by moving it inside lock_sock()/release_sock(), matching the pattern used in iso_conn_del() and all other call sites.

References

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