Is CVE-2021-43400 in the CISA KEV catalog?

No. CVE-2021-43400 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-43400?

CVE-2021-43400 has a CVSS v3 base score of 9.1 (CRITICAL).

What is the EPSS score for CVE-2021-43400?

CVE-2021-43400 has an EPSS score of 1.54% (72th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-43400?

Upgrade bluez on debian 11 to 5.55-3.1+deb11u2 or later. Fixes are available for 3 affected products.

CVE & CISA-KEV Catalog

CVE-2021-43400

CRITICALEPSS 72th pctl

9.1

CVSS v3

NVD

Description

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.

CWE-416Use After Free

How to fix

Remediation Available

bluezDebian

Fixed in:5.55-3.1+deb11u2CVE-2021-43400

Fixed in:5.62-1CVE-2021-43400

bluezUbuntu

Fixed in:5.48-0ubuntu3.6USN-5155-1

Fixed in:5.53-0ubuntu3.4USN-5155-1

libbluetooth3Ubuntu

Fixed in:5.48-0ubuntu3.6USN-5155-1

Fixed in:5.53-0ubuntu3.4USN-5155-1

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityNone

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

Exploit Intelligence

1.54%probability of exploitation in 30 days

72ndpercentile

Elevated risk: more likely to be exploited than 72% of all known CVEs.

References

Patch1

git.kernel.org

Third-Party Advisory1

lists.debian.org

Other references1

lists.debian.org

Related Vulnerabilities

Other CWE-416 (Use After Free) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2019-0708	Critical	9.8	100%	KEV + Ransom	-
CVE-2021-31166	Critical	9.8	100%	KEV	Fix
CVE-2015-5119	Critical	9.8	99%	KEV	-
CVE-2010-3962	High	8.1	97%	KEV	-
CVE-2015-0313	Critical	9.8	96%	KEV	Fix
CVE-2017-9798	High	7.5	95%	-	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-11-04.