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NVD / CVE Program· CNA Linux

CVE-2026-90091: Bluetooth: L2CAP: fix race l2cap_sock_cleanup_listen() vs. put_chan

Noroxi assessment

Priority: Monitor (action score 32/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.36% (FIRST EPSS).
  • Someone on the same network segment can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 32a7bc6e93be36b37fe61f351d312d358195bd61, 4f8c63fe0097c9f6ea34409f82f79b3894903d91, 6.1.188; azl3 kernel 6.6.152.1-1 on Azure Linux 3.0 6.6.157.1-1.

Low priority for now. Upgrade to Linux Linux 32a7bc6e93be36b37fe61f351d312d358195bd61, 4f8c63fe0097c9f6ea34409f82f79b3894903d91, 6.1.188; azl3 kernel 6.6.152.1-1 on Azure Linux 3.0 6.6.157.1-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: fix race l2cap_sock_cleanup_listen() vs. put_chan For L2CAP sockets without owning sk->sk_socket, reading l2cap_pi(sk)->chan may race against concurrent l2cap_sock_kill() -> l2cap_sock_put_chan(). This excludes simultaneous proto_ops callbacks, but access in l2cap_sock_cleanup_listen() has unsafe lockless read. [Task 1] [Task 2 (hdev->workqueue)] l2cap_sock_release(parent) l2cap_disconn_cfm l2cap_sock_cleanup_listen l2cap_conn_del bt_accept_dequeue l2cap_chan_del lock_sock(sk) l2cap_sock_teardown_cb bt_accept_unlink bt_sk(sk)->parent = NULL release_sock(sk) ----------------> lock_sock(sk) parent = /* NULL */ lock_sock(sk) <--------------------- release_sock(sk) sock_set_flag(sk, SOCK_ZAPPED) l2cap_sock_close_cb l2cap_sock_kill(sk) l2cap_sock_put_chan chan = READ l2cap_pi(sk)->chan l2cap_pi(sk)->chan = NULL l2cap_chan_hold_unless_zero l2cap_put_chan(chan) kref_get_unless_zero(&chan->ref) Task 1 may observe NULL which causes null-ptr-deref. Fix the race by taking lock_sock() in l2cap_sock_kill() to synchronize with l2cap_sock_cleanup_listen(). hold_unless_zero() is not needed here, l2cap_pi(sk)->chan owns reference if it is non-NULL. Clarify code comments vs. locking.

HighCVSS 8.0 · v3.1—No exploit Fix available
Published
Sep 17, 2026
Updated
Oct 19, 2026
EPSS
0.3% · 30th percentile
CWE
—

Report tools

JSON

Action score

32

Monitor

Low priority for now.

CVSS
32 / 40 · 8.0 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.3%

CNA vs NVD score

NVD
—
CNA · Linux
8.0
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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  • A fix has been released

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Noroxi analysis

What does it mean in your environment?

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 733e76e74e406c1d1ddc7369420dd8a47f48bb8a, 7.2affected
    • b39298044e5534612511a2ff5de03ba5f6e7a820 and later · before 827de6bd2865b22aaabd554540def3b8a33018abaffected · git
    • 8c37e4338c801ebb8cee52436c01c41e009f6e87 and later · before 7c7ac736b50fa259ed1bdddc18d79523f07c0442affected · git
    • 84e718b6a814edc84159361f9f454a4e92ae91ae and later · before 4f8c63fe0097c9f6ea34409f82f79b3894903d91affected · git
    • 36da806f7fbaee56ad9e81859deec203f9728700 and later · before 61d5ddbd524c715b224cbe7e9f01da4e05098b19affected · git
    • 6fef032af0092ed5ccb767239a9ac1bc38c08a40 and later · before 32a7bc6e93be36b37fe61f351d312d358195bd61affected · git
    • 6fef032af0092ed5ccb767239a9ac1bc38c08a40 and later · before 66d6ef18548ae6d7dd452b84115fc82c0a73a4eaaffected · git
    • 6.1.178 and later · before 6.1.188affected · semver
    • 6.6.145 and later · before 6.6.157affected · semver
    • 6.12.97 and later · before 6.12.110affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.190-16.1.190-1
Debian:12linux-6.12before 6.12.111-1~deb12u16.12.111-1~deb12u1
Debian:13linuxbefore 6.12.111-16.12.111-1
Debian:14linuxbefore 7.2.6-17.2.6-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-90089Sep 17, 2026 · Bluetooth: btnxpuart: Validate the FW dump header length
    28Monitor
  • ← EarlierCVE-2026-90090Sep 17, 2026 · Bluetooth: btmtksdio: Fix out-of-bounds DMA read in the TX path
    0Monitor
  • Later →CVE-2026-90092Sep 17, 2026 · Bluetooth: L2CAP: reject accept queue add unless BT_LISTEN
    32Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux32a7bc6e93be36b37fe61f351d312d358195bd61Vendor (CNA)
Linux Linux4f8c63fe0097c9f6ea34409f82f79b3894903d91Vendor (CNA)
Linux Linux6.1.188Vendor (CNA)
Linux Linux6.12.110Vendor (CNA)
Linux Linux6.18.52Vendor (CNA)
Linux Linux6.6.157Vendor (CNA)
Linux Linux61d5ddbd524c715b224cbe7e9f01da4e05098b19Vendor (CNA)
Linux Linux66d6ef18548ae6d7dd452b84115fc82c0a73a4eaVendor (CNA)
Linux Linux7.2Vendor (CNA)
Linux Linux7c7ac736b50fa259ed1bdddc18d79523f07c0442Vendor (CNA)
Linux Linux827de6bd2865b22aaabd554540def3b8a33018abVendor (CNA)
azl3 kernel 6.6.150.1-1 on Azure Linux 3.0—Microsoft (MSRC)
azl3 kernel 6.6.152.1-1 on Azure Linux 3.06.6.157.1-1 · Release NotesMicrosoft (MSRC)
debian:linux6.1.190-1 · Debian:12Package registry (OSV)
debian:linux6.12.111-1 · Debian:13Package registry (OSV)
debian:linux-6.126.12.111-1~deb12u1 · Debian:12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone on the same network segment can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Adjacent
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

—

CVSS vector

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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

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References

Show all references (5 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records