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Vulnerability record · CVE-2026-66749 · published 28 July 2026

CVE-2026-66749: NULL pointer dereference vulnerability

Let's Chat 0.4.0 through 0.4.8 contains a null dereference vulnerability that allows authenticated attackers to crash the server by supplying a valid 24-character hex string room parameter that matches no document in the database. Attackers can send a crafted GET /messages request causing an uncaught TypeError in an asynchronous Mongoose callback that terminates the Node.js server process, with the same defect reachable through multiple code paths including the socket.io interface.

7.1 CVSS 4.0 High EPSS 0.44% · top 64.6% CWE-476 · NULL pointer dereference Deferred
7.1CVSS 4.0 base score
0.44%EPSS exploitation probability, 30 days
NoNot in CISA KEV
0Affected product versions listed by NVD
2References
30 Jul 2026Last modified by NVD

Description

Let's Chat 0.4.0 through 0.4.8 contains a null dereference vulnerability that allows authenticated attackers to crash the server by supplying a valid 24-character hex string room parameter that matches no document in the database. Attackers can send a crafted GET /messages request causing an uncaught TypeError in an asynchronous Mongoose callback that terminates the Node.js server process, with the same defect reachable through multiple code paths including the socket.io interface.

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/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:

References

LinkTags
https://github.com/theopaid/Unchecked-Room-Lookup-Leads-to-Server-Crash-Let-s-Chat-
https://www.vulncheck.com/advisories/let-s-chat-denial-of-service-via-null-dereference-in-room-lookup

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

6.2CVE-2026-21525Windows Remote Access Connection Manager null pointer dereference DoSWindows Remote Access Connection Manager contains a null pointer dereference (CWE-476) that lets an unauthorized attacker deny service locally. The f…KEVEPSS 4.8%analysed

Source: NIST National Vulnerability Database (record CVE-2026-66749), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.