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CVE Record

CVE-2021-43400: An issue was discovered in gatt-database.c in BlueZ 5.61.

An issue was discovered in gatt-database.c in BlueZ 5.61. A use-after-free can occur when a client disconnects during D-Bus processing of a WriteValue call.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2021-43400 is a BlueZ flaw where a client disconnecting during D-Bus WriteValue handling can trigger a use-after-free. The public record does not provide a CVSS score, quantified impact, or confirmed affected range beyond BlueZ 5.61 being named.

Executive priority

Treat this as a routine-to-important Bluetooth stack update, not an emergency based on current evidence. Prioritize exposed Linux systems using Bluetooth services, especially managed endpoints and appliances that may lag on OS security updates.

Technical view

The issue is in gatt-database.c in BlueZ 5.61. During D-Bus processing of a GATT WriteValue call, client disconnection can leave freed memory referenced. The cited BlueZ commit and Debian LTS advisories are the available remediation references, but the bundle does not detail exploitability or impact class.

Likely exposure

Exposure is most plausible on systems running affected BlueZ Bluetooth components with GATT/D-Bus WriteValue paths enabled. Debian LTS advisories indicate bluez security updates were shipped. The source bundle does not identify all vendors, distributions, configurations, or version ranges affected.

Exploitation context

No provided source says this is actively exploited, and KEV status is false. Public evidence supports a memory-safety bug triggered by a disconnect timing condition, but not weaponized exploitation, privilege impact, remote reachability, or reliable attack prerequisites.

Researcher notes

Evidence is thin: no CVSS, CWE, affected CPEs, or exploit status are provided. Analysis should stay anchored to the named BlueZ 5.61 gatt-database.c use-after-free and the Debian security update trail until vendor advisories add impact details.

Mitigation direction

  • Apply vendor BlueZ security updates for affected distributions.
  • Review Debian LTS bluez advisories if using Debian-derived systems.
  • Check the referenced upstream BlueZ commit for fixed code lineage.
  • Disable unnecessary Bluetooth services where operationally acceptable.
  • Monitor vendor guidance for affected version clarification.

Validation and detection

  • Inventory systems with BlueZ or distro bluez packages installed.
  • Compare installed package versions against vendor security advisories.
  • Confirm deployed builds include the referenced upstream fix.
  • Review Bluetooth/GATT service exposure on managed endpoints.
  • Document systems where Bluetooth is disabled or unavailable.
Prepared
Confidence
medium
Sources
5

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

description · low confidence lookup

Database behavior lookup

The CVE wording references database injection or access, so collection and exfiltration review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2021-43400 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
0Timeline events
0ADP providers
4Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.