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NVD / CVE Program· CNA Linux

CVE-2026-43134: Bluetooth: L2CAP: Fix missing key size check for L2CAP_LE_CONN_REQ

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: 0.11% (FIRST EPSS).
  • Someone on the same network segment can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 138d7eca445ef37a0333425d269ee59900ca1104, 335071c0c3637064ec250481f589075db44fe4e6, 481ea39b342c347b6ac029f3d418486280be4e45.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 138d7eca445ef37a0333425d269ee59900ca1104, 335071c0c3637064ec250481f589075db44fe4e6, 481ea39b342c347b6ac029f3d418486280be4e45 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 missing key size check for L2CAP_LE_CONN_REQ This adds a check for encryption key size upon receiving L2CAP_LE_CONN_REQ which is required by L2CAP/LE/CFC/BV-15-C which expects L2CAP_CR_LE_BAD_KEY_SIZE.

HighCVSS 8.1 · v3.1—No exploit Fix available
Published
May 6, 2026
Updated
Oct 19, 2026
EPSS
0.1% · 1th percentile

Report tools

JSON

Action score

32

Monitor

Low priority for now.

CVSS
32 / 40 · 8.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · Linux
8.1
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.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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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.

VendorProduct
linuxlinux kernel

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Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel3.14 and later · before 5.10.252
  • linux linux kernel5.11 and later · before 5.15.202
  • linux linux kernel5.16 and later · before 6.1.165
  • linux linux kernel6.2 and later · before 6.6.128
  • linux linux kernel6.7 and later · before 6.12.75
  • linux linux kernel6.13 and later · before 6.18.16
  • linux linux kernel6.19 and later · before 6.19.6
  • linux linux kernel7.0

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

    • 3.14affected
    • 27e2d4c8d28be1d1b4ecfbffab572d7dbd35254d and later · before 335071c0c3637064ec250481f589075db44fe4e6affected · git
    • 27e2d4c8d28be1d1b4ecfbffab572d7dbd35254d and later · before fa6ad76fa8623c0a50d529cd5726fa5d819a3be4affected · git
    • 27e2d4c8d28be1d1b4ecfbffab572d7dbd35254d and later · before 9118601ff90b79e8df3c0c98f48ae00c1b02ecefaffected · git
    • 27e2d4c8d28be1d1b4ecfbffab572d7dbd35254d and later · before 481ea39b342c347b6ac029f3d418486280be4e45affected · git
    • 27e2d4c8d28be1d1b4ecfbffab572d7dbd35254d and later · before ec91078e132179b04e0c3906b599816c056ceaadaffected · git
    • 27e2d4c8d28be1d1b4ecfbffab572d7dbd35254d and later · before 96581749c7c14fbec32c35728520867929600041affected · git
    • 27e2d4c8d28be1d1b4ecfbffab572d7dbd35254d and later · before 8dd43f9a9323f9c01bc8246da8d81a4c783c9e97affected · git
    • 27e2d4c8d28be1d1b4ecfbffab572d7dbd35254d and later · before 138d7eca445ef37a0333425d269ee59900ca1104affected · git
    • before 3.14not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.170-16.1.170-1
Debian:13linuxbefore 6.12.85-16.12.85-1
Debian:14linuxbefore 6.19.6-16.19.6-1
SUSE:Linux Enterprise Live Patching 12 SP5kernel-defaultbefore 4.12.14-122.328.14.12.14-122.328.1
SUSE:Linux Enterprise Live Patching 12 SP5kgraft-patch-SLE12-SP5_Update_87before 1-8.5.11-8.5.1
SUSE:Linux Enterprise Server 12 SP5-LTSSkernel-sourcebefore 4.12.14-122.328.14.12.14-122.328.1
SUSE:Linux Enterprise Server 12 SP5-LTSSkernel-symsbefore 4.12.14-122.328.14.12.14-122.328.1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe…KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2026-43132May 6, 2026 · dm-verity: correctly handle dm_bufio_client_create() failure
    22Monitor
  • ← EarlierCVE-2026-43133May 6, 2026 · KVM: nSVM: Always use vmcb01 in VMLOAD/VMSAVE emulation
    31Monitor
  • Later →CVE-2026-43135May 6, 2026 · media: cx23885: Add missing unmap in snd_cx23885_hw_params()
    22Monitor

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 Linux138d7eca445ef37a0333425d269ee59900ca1104Vendor (CNA)
Linux Linux335071c0c3637064ec250481f589075db44fe4e6Vendor (CNA)
Linux Linux481ea39b342c347b6ac029f3d418486280be4e45Vendor (CNA)
Linux Linux8dd43f9a9323f9c01bc8246da8d81a4c783c9e97Vendor (CNA)
Linux Linux9118601ff90b79e8df3c0c98f48ae00c1b02ecefVendor (CNA)
Linux Linux96581749c7c14fbec32c35728520867929600041Vendor (CNA)
Linux Linuxec91078e132179b04e0c3906b599816c056ceaadVendor (CNA)
Linux Linuxfa6ad76fa8623c0a50d529cd5726fa5d819a3be4Vendor (CNA)
debian:linux6.1.170-1 · Debian:12Package registry (OSV)
suse:kernel-default4.12.14-122.328.1 · SUSE:Linux Enterprise Live Patching 12 SP5Package registry (OSV)
suse:kernel-source4.12.14-122.328.1 · SUSE:Linux Enterprise Server 12 SP5-LTSSPackage registry (OSV)
suse:kernel-syms4.12.14-122.328.1 · SUSE:Linux Enterprise Server 12 SP5-LTSSPackage registry (OSV)
suse:kgraft-patch-SLE12-SP5_Update_871-8.5.1 · SUSE:Linux Enterprise Live Patching 12 SP5Package 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.

No history yet (it accumulates with the daily EPSS job).

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.

  • CVE-2025-39889224 days apartBluetooth: l2cap: Check encryption key size on incoming connection
    22Monitor

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).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

Attack conditions

  • Someone on the same network segment can trigger it.
  • No account or password is required.
  • 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
none
Attack vector
Adjacent
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
None

Weakness class (CWE)

CWE-326 · Inadequate Encryption Strength

CVSS vector

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

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.

ATT&CK techniques

Change log

  1. SSVC exploitation— → none
  2. Fix✗ → ✓

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

References

Show all references (7 more)

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

All records