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NVD / CVE Program· CNA Linux

CVE-2026-99239: Bluetooth: L2CAP: refuse __l2cap_chan_add if chan already has conn

Noroxi assessment

Priority: Monitor (action score 31/100)

  • 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: 0.12% (FIRST EPSS).
  • Someone with local access to the system 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 10c705dd706aa93164ba41f2566f15206d6c178e, 5.10.273, 5.15.224.

Low priority for now. Upgrade to Linux Linux 10c705dd706aa93164ba41f2566f15206d6c178e, 5.10.273, 5.15.224 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: refuse __l2cap_chan_add if chan already has conn l2cap_chan may be linked to l2cap_conn at most once. This is assumed in several places, eg l2cap_chan_del cleanup. There is a TOCTOU race where the invariant is violated: [Task 1] [Task 2] l2cap_chan_connect l2cap_sock_bind l2cap_chan_lock lock_sock l2cap_state_change if (sk->sk_state != BT_OPEN) chan->state = BT_CONNECT l2cap_sock_state_change_cb chan->state = BT_BOUND sk->sk_state = BT_BOUND lock_sock <------------------ release_sock sk->sk_state = BT_CONNECT l2cap_sock_connect() does not check sk->sk_state, so since chan->state is now BT_BOUND, subsequent connect() ends up with second __l2cap_chan_add. Explicitly document and check the invariant in __l2cap_chan_add with WARN_ON_ONCE. The only callsite where it could be hit is l2cap_chan_connect, so add pre-check there to avoid relying on chan->state. chan->state read/write is not properly guarded currently so there can be other TOCTOUC problems. Add l2cap_lock_chan in l2cap_sock_bind() to guard chan->state write.

HighCVSS 7.8 · v3.1—No exploit Fix available
Published
Nov 2, 2026
Updated
Nov 3, 2026
EPSS
0.1% · 1th percentile
CWE
—

Report tools

JSON

Action score

31

Monitor

Low priority for now.

CVSS
31 / 40 · 7.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CNA vs NVD score

NVD
—
CNA · Linux
7.8
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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  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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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

    • 50c38d9f42a529691e4e67ea9cedf4f0bfc8d277, 7.2affected
    • 8f90405a4a6f1f1880dc07996b47bf57c712bd8a and later · before 85cc289eb08afa975375f838187369e68b429ee0affected · git
    • 32d783cafb46ff3ca58e6f9fd62c9c5f35eaf26b and later · before 820579652b24ce277e0097cd65b42bd9b7b8bf07affected · git
    • 8922c7940bae9ce4b1736dddb6362370793835c2 and later · before e618d928ec7f88cbeadfa3542adcac40f474e629affected · git
    • 91047a4396a8b1857a6f712a90cf33ec0012b189 and later · before fabaff1c59ff2cc89cb7e5bd0186a5e15f0c73b2affected · git
    • 0b0e2bf39cf99e458d991b9df253727e036a7d7d and later · before 52fe88e4ef87311eee32b45c65603e7c69e75e7daffected · git
    • d3b739db5dc6f688a60d56da872fabaf65246032 and later · before 10c705dd706aa93164ba41f2566f15206d6c178eaffected · git
    • b66774b48dd98f07254951f74ea6f513efe7ff8b and later · before 73820561d8cbfd3364a29b8fa77f1707f26029daaffected · git
    • b66774b48dd98f07254951f74ea6f513efe7ff8b and later · before d3afd7803f9bc2a8c4270199497b60158b2fc647affected · git
    • b66774b48dd98f07254951f74ea6f513efe7ff8b and later · before 86b55991d3cd690e73c5ef8d20b75ae4905b357aaffected · git

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxfrom 0—
Debian:13linuxbefore 6.12.115-16.12.115-1

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-2026-99237Nov 2, 2026 · tracing: Hold trace_types_lock when resetting last boot data from readers
    31Monitor
  • ← EarlierCVE-2026-99238Nov 2, 2026 · tracing: Hold trace_types_lock when updating modules in persistent instances
    31Monitor
  • Later →CVE-2026-99240Nov 2, 2026 · mm/damon/core: error damos_commit_quota_goal() for zero target_value
    0Monitor

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 Linux10c705dd706aa93164ba41f2566f15206d6c178eVendor (CNA)
Linux Linux5.10.273Vendor (CNA)
Linux Linux5.15.224Vendor (CNA)
Linux Linux52fe88e4ef87311eee32b45c65603e7c69e75e7dVendor (CNA)
Linux Linux6.1.191Vendor (CNA)
Linux Linux6.12.115Vendor (CNA)
Linux Linux6.18.60Vendor (CNA)
Linux Linux6.6.161Vendor (CNA)
Linux Linux7.2Vendor (CNA)
Linux Linux73820561d8cbfd3364a29b8fa77f1707f26029daVendor (CNA)
Linux Linux820579652b24ce277e0097cd65b42bd9b7b8bf07Vendor (CNA)
Linux Linux85cc289eb08afa975375f838187369e68b429ee0Vendor (CNA)
Linux Linux86b55991d3cd690e73c5ef8d20b75ae4905b357aVendor (CNA)
Linux Linuxd3afd7803f9bc2a8c4270199497b60158b2fc647Vendor (CNA)
Linux Linuxe618d928ec7f88cbeadfa3542adcac40f474e629Vendor (CNA)
Linux Linuxfabaff1c59ff2cc89cb7e5bd0186a5e15f0c73b2Vendor (CNA)
debian:linux6.12.115-1 · Debian:13Package 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.

  1. Published
  2. Fix recordedsame day
  3. TodayNov 5, 2026+2 d
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.

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Bug bounty scope

No known public program.

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

Technical details

Attack conditions

  • Someone with local access to the system 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
Local
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:L/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✗ → ✓
  2. Exploit maturity— → none

For records you follow, these changes also arrive as notifications. →

References

Show all references (8 more)

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

All records