CVE-2021-31612

The Bluetooth Classic implementation on Zhuhai Jieli AC690X devices does not properly handle the reception of an oversized LMP packet greater than 17 bytes during the LMP auto rate procedure, allowing attackers in radio range to trigger a deadlock via a crafted LMP packet.

Published: 2021-09-07 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-31612 is rated Moderate Risk (40.2/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.51%). 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-2021-31612

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 0.13% 0.51% +0.38%
2 2025-03-30 0.19% 0.13% -0.06%
3 2025-03-29 — 0.19% —

Full EPSS history (8 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-31612

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.5 3.1 MEDIUM
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:A)
Attacker has to be nearby on the network—same office, same link, that vibe—not the whole wide internet.
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:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.8 3.6 [email protected]
6.1 2.0 MEDIUM
AV:A/AC:L/Au:N/C:N/I:N/A:C Click to expand
Access vector (AV:A)
Requires access to an adjacent network segment.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:C)
Complete availability impact.
 6.5 6.9 [email protected]

Weakness enumeration for CVE-2021-31612

Affected software / configurations for CVE-2021-31612

Vendor Product Version Raw CPE
zh-jieli ac6901_firmware — cpe:2.3:o:zh-jieli:ac6901_firmware:-:*:*:*:*:*:*:*
zh-jieli ac690n_firmware — cpe:2.3:o:zh-jieli:ac690n_firmware:-:*:*:*:*:*:*:*
zh-jieli ac692n_firmware — cpe:2.3:o:zh-jieli:ac692n_firmware:-:*:*:*:*:*:*:*
zh-jieli ac6902_firmware — cpe:2.3:o:zh-jieli:ac6902_firmware:-:*:*:*:*:*:*:*
zh-jieli ac6903_firmware — cpe:2.3:o:zh-jieli:ac6903_firmware:-:*:*:*:*:*:*:*
zh-jieli ac6905_firmware — cpe:2.3:o:zh-jieli:ac6905_firmware:-:*:*:*:*:*:*:*
zh-jieli ac6904_firmware — cpe:2.3:o:zh-jieli:ac6904_firmware:-:*:*:*:*:*:*:*
zh-jieli ac6907_firmware — cpe:2.3:o:zh-jieli:ac6907_firmware:-:*:*:*:*:*:*:*
zh-jieli ac6908_firmware — cpe:2.3:o:zh-jieli:ac6908_firmware:-:*:*:*:*:*:*:*
zh-jieli ac6997_firmware — cpe:2.3:o:zh-jieli:ac6997_firmware:-:*:*:*:*:*:*:*
zh-jieli ac6998_firmware — cpe:2.3:o:zh-jieli:ac6998_firmware:-:*:*:*:*:*:*:*
zh-jieli ac6999_firmware — cpe:2.3:o:zh-jieli:ac6999_firmware:-:*:*:*:*:*:*:*

References for CVE-2021-31612

cvelogic Threat Intelligence