PT-2026-39199 · Flashmq · Flashmq

Ruoyyy · CVE-2026-42209 · Published 2026-05-08 · Updated 2026-05-09

Positive Technologies (AI Summary)

CVSS v3.1

6.5

Medium

Base vector

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

Name of the Vulnerable Software and Affected Versions FlashMQ versions prior to 1.26.1

Description A remote client with retained publish permission can cause a denial of service by crashing the broker. This occurs when both set retained message defer timeout and set retained message defer timeout spread are configured to non-default values. If anonymous retained publishing is enabled, no authentication is required to trigger the crash; otherwise, the attacker must possess the necessary publish permissions.

Recommendations Update to version 1.26.1.

Exploit

Fix

DoS

Divide By Zero

Weakness Enumeration

CWE-369

Related Identifiers

CVE-2026-42209

GHSA-2789-VFCG-5922

Affected Products

Flashmq

References · 9

• 🔥 https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42209.json · Exploit
• 🔥 https://github.com/halfgaar/FlashMQ/issues/167 · Exploit
• https://osv.dev/vulnerability/CVE-2026-42209 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-42209 · Security Note
• https://github.com/halfgaar/FlashMQ/security/advisories/GHSA-2789-vfcg-5922 · Note
• https://github.com/halfgaar/FlashMQ/commit/193b6e7767889511cfa8e933908ea5e6a1077a1f · Note
• https://github.com/halfgaar/FlashMQ/releases/tag/v1.26.1 · Note
• https://twitter.com/CVEnew/status/2053131434957893645 · Twitter Post
• https://twitter.com/VulmonFeeds/status/2052980832344617006 · Twitter Post