CVE-2026-8741

EMQX QoS 2 PUBLISH Packet emqx_persistent_session_ds.erl race condition

A vulnerability has been found in EMQX up to 6.2.0. This affects an unknown function of the file apps/emqx/src/emqx_persistent_session_ds.erl of the component QoS 2 PUBLISH Packet Handler. Such manipulation leads to race condition. The attack may be performed from remote. A high complexity level is associated with this attack. The exploitability is reported as difficult. The exploit has been disclosed to the public and may be used. The vendor was contacted early about this disclosure.

Affected

EMQX

CVSS v4.0 VULDB

1.3 LOWCVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS v3.1 VULDB

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

CVSS v2.0 VULDB

2.1 LOWAV:N/AC:H/Au:S/C:N/I:N/A:P

EPSS

0.39% chance of exploitation in the next 30 days, 32nd percentile

Published

2026-05-17

Updated

2026-05-18

Proof-of-concept exploits (1)

• Pathfind-tama/Report_EMQX_MQTT/blob/main/MQTT%20QoS%202%20Message%20Duplication%20in%20Pe…

Security advisories

• https://vuldb.com/submit/809931
• https://vuldb.com/vuln/364329

References

• CVE Record
• NVD entry