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NVD / CVE Program· CNA Linux

CVE-2024-26903: Bluetooth: rfcomm: Fix null-ptr-deref in rfcomm_check_security

Noroxi assessment

Priority: Monitor (action score 22/100)

  • 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: 0.27% (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 2535b848fa0f42ddff3e5255cf5e742c9b77bb26, 369f419c097e82407dd429a202cde9a73d3ae29b, 3ead59bafad05f2967ae2438c0528d53244cfde5.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 2535b848fa0f42ddff3e5255cf5e742c9b77bb26, 369f419c097e82407dd429a202cde9a73d3ae29b, 3ead59bafad05f2967ae2438c0528d53244cfde5 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: rfcomm: Fix null-ptr-deref in rfcomm_check_security During our fuzz testing of the connection and disconnection process at the RFCOMM layer, we discovered this bug. By comparing the packets from a normal connection and disconnection process with the testcase that triggered a KASAN report. We analyzed the cause of this bug as follows: 1. In the packets captured during a normal connection, the host sends a `Read Encryption Key Size` type of `HCI_CMD` packet (Command Opcode: 0x1408) to the controller to inquire the length of encryption key.After receiving this packet, the controller immediately replies with a Command Completepacket (Event Code: 0x0e) to return the Encryption Key Size. 2. In our fuzz test case, the timing of the controller's response to this packet was delayed to an unexpected point: after the RFCOMM and L2CAP layers had disconnected but before the HCI layer had disconnected. 3. After receiving the Encryption Key Size Response at the time described in point 2, the host still called the rfcomm_check_security function. However, by this time `struct l2cap_conn *conn = l2cap_pi(sk)->chan->conn;` had already been released, and when the function executed `return hci_conn_security(conn->hcon, d->sec_level, auth_type, d->out);`, specifically when accessing `conn->hcon`, a null-ptr-deref error occurred. To fix this bug, check if `sk->sk_state` is BT_CLOSED before calling rfcomm_recv_frame in rfcomm_process_rx.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Apr 17, 2024
Updated
Oct 15, 2026
EPSS
0.2% · 20th percentile

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
5.5
CNA · Linux
5.5
agree

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

Affected versions

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

  • linux linux kernelbefore 4.19.311
  • linux linux kernel4.20 and later · before 5.4.273
  • linux linux kernel5.5 and later · before 5.10.214
  • linux linux kernel5.11 and later · before 5.15.153
  • linux linux kernel5.16 and later · before 6.1.83
  • linux linux kernel6.2 and later · before 6.6.23
  • linux linux kernel6.7 and later · before 6.7.11

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

    • 2.6.12affected
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 369f419c097e82407dd429a202cde9a73d3ae29baffected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 5f369efd9d963c1f711a06c9b8baf9f5ce616d85affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 81d7d920a22fd58ef9aedb1bd0a68ee32bd23e96affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 8d1753973f598531baaa2c1033cf7f7b5bb004b0affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 567c0411dc3b424fc7bd1e6109726d7ba32d4f73affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 3ead59bafad05f2967ae2438c0528d53244cfde5affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 5f9fe302dd3a9bbc50f4888464c1773f45166bfdaffected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 2535b848fa0f42ddff3e5255cf5e742c9b77bb26affected · git
    • before 2.6.12not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.82-16.1.82-1
Debian:13linuxbefore 6.7.12-16.7.12-1

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-2024-26901Apr 17, 2024 · do_sys_name_to_handle(): use kzalloc() to fix kernel-infoleak
    22Monitor
  • ← EarlierCVE-2024-26902Apr 17, 2024 · perf: RISCV: Fix panic on pmu overflow handler
    22Monitor
  • Later →CVE-2024-26906Apr 17, 2024 · x86/mm: Disallow vsyscall page read for copy_from_kernel_nofault()
    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 Linux2535b848fa0f42ddff3e5255cf5e742c9b77bb26Vendor (CNA)
Linux Linux369f419c097e82407dd429a202cde9a73d3ae29bVendor (CNA)
Linux Linux3ead59bafad05f2967ae2438c0528d53244cfde5Vendor (CNA)
Linux Linux567c0411dc3b424fc7bd1e6109726d7ba32d4f73Vendor (CNA)
Linux Linux5f369efd9d963c1f711a06c9b8baf9f5ce616d85Vendor (CNA)
Linux Linux5f9fe302dd3a9bbc50f4888464c1773f45166bfdVendor (CNA)
Linux Linux81d7d920a22fd58ef9aedb1bd0a68ee32bd23e96Vendor (CNA)
Linux Linux8d1753973f598531baaa2c1033cf7f7b5bb004b0Vendor (CNA)
debian:linux6.1.82-1 · 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.

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.

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).

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 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
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-476 · NULL Pointer Dereference

CVSS vector

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

nvd-primary

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✗ → ✓

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

References

Show all references (10 more)

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

All records