VulnerabilityPublished 25 Jun 2026Updated 6 Nov 2026

CVE-2026-53251: Linux kernel · Bluetooth: ISO: Fix not releasing hdev reference on iso_conn_big_sync

Affects Linux kernelSource CVE Database V5

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Not known to be exploited · fixed in 33d677d2e3713d98012c3dbd4a9207f7d785b854 : update Linux kernel when convenient.

Data as of 6 Nov 2026, 16:49 UTC

Severity

Unrated

Rated by Threat Radar · No CVSS score from NVD or the CNA

Thin evidence

One scorer or none

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: Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-11-06.

Patch

Available – fixed in 33d677d2e3713d98012c3dbd4a9207f7d785b854, 23e8eb16820b866528fb300dc67fe3f67f00ef62, 6.12.94 +3

Exploitation evidence

Disclosed: evidence found.
CVE published 25 Jun 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 6 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected >=6.12.2 <6.12.94 >=6.11.11 <6.12	Fixed in 33d677d2e3713d98012c3dbd4a9207f7d785b854 23e8eb16820b866528fb300dc67fe3f67f00ef62 6.12.94 6.12 5cbf290b79351971f20c7a533247e8d58a3f970c 4bbec25f47b930101294fd310c627c3f53e9661f
LinuxLinux	Affected =6.13	Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: ISO: Fix not releasing hdev reference on iso_conn_big_sync hci_get_route() returns a reference-counted hci_dev pointer via hci_dev_hold(). The function exits normally or with an error without ever releasing it.

References

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