CVE-2021-43400

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.

Published: 2021-11-04 Last update: 2025-11-04 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-43400 is rated Moderate Risk (62.8/100): CVSS Critical severity, with medium exploitation likelihood (EPSS 1.54%). EPSS rose +1.37% over the last day, indicating growing attacker interest. Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-43400

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.17% 1.54% +1.37%
2 2026-01-07 0.15% 0.17% +0.02%
3 2025-11-21 — 0.15% —

Full EPSS history (14 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-43400

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.1 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 5.2 [email protected]
6.4 2.0 MEDIUM
AV:N/AC:L/Au:N/C:P/I:P/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:N)
No availability impact.
 10.0 4.9 [email protected]

Weakness enumeration for CVE-2021-43400

OS Trackers for CVE-2021-43400

vendor priority summary link
debian not yet assigned CVE-2021-43400 not yet assigned priority: Debian including 1 source packages (bluez), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2021-43400
redhat medium — https://access.redhat.com/security/cve/CVE-2021-43400
suse medium CVE-2021-43400 severity moderate: SUSE including 20 source package names (bluez, bluez-5.48-150000.5.41.1, …), 123 product×package rows across 52 product lines (HPE Helion OpenStack 8, SUSE CaaS Platform 4.0, … (52 product lines)): Fixed 74, Known Not Affected 49. https://www.suse.com/security/cve/CVE-2021-43400/
ubuntu medium CVE-2021-43400 medium priority: Ubuntu including 1 source packages (bluez), 15 status rows across 15 suites (bionic, focal, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): not-affected 8, released 4, ignored 1, needed 1, needs-triage 1. https://ubuntu.com/security/CVE-2021-43400

Affected software / configurations for CVE-2021-43400

Vendor Product Version Raw CPE
bluez bluez 5.61 cpe:2.3:a:bluez:bluez:5.61:*:*:*:*:*:*:*
debian debian_linux 10.0 cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*

References for CVE-2021-43400

cvelogic Threat Intelligence